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nginx/src/core/ngx_resolver.c
Aleksei Bavshin f2fcc03d3a Resolver: make TCP write timer event cancelable. 
Similar to 70e65bf8dfd7, the change is made to ensure that the ability to
cancel resolver tasks is fully controlled by the caller.  As mentioned in the
referenced commit, it is safe to make this timer cancelable because resolve
tasks can have their own timeouts that are not cancelable.

The scenario where this may become a problem is a periodic background resolve
task (not tied to a specific request or a client connection), which receives a
response with short TTL, large enough to warrant fallback to a TCP query.
With each event loop wakeup, we either have a previously set write timer
instance or schedule a new one.  The non-cancelable write timer can delay or
block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable
flag is set by the API user, and there are no other tasks or connections.

We use the resolver API in this way to maintain the list of upstream server
addresses specified with the 'resolve' parameter, and there could be third-party
modules implementing similar logic.
2022-06-01 20:17:23 -07:00

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/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#define NGX_RESOLVER_UDP_SIZE 4096
#define NGX_RESOLVER_TCP_RSIZE (2 + 65535)
#define NGX_RESOLVER_TCP_WSIZE 8192
typedef struct {
u_char ident_hi;
u_char ident_lo;
u_char flags_hi;
u_char flags_lo;
u_char nqs_hi;
u_char nqs_lo;
u_char nan_hi;
u_char nan_lo;
u_char nns_hi;
u_char nns_lo;
u_char nar_hi;
u_char nar_lo;
} ngx_resolver_hdr_t;
typedef struct {
u_char type_hi;
u_char type_lo;
u_char class_hi;
u_char class_lo;
} ngx_resolver_qs_t;
typedef struct {
u_char type_hi;
u_char type_lo;
u_char class_hi;
u_char class_lo;
u_char ttl[4];
u_char len_hi;
u_char len_lo;
} ngx_resolver_an_t;
#define ngx_resolver_node(n) ngx_rbtree_data(n, ngx_resolver_node_t, node)
static ngx_int_t ngx_udp_connect(ngx_resolver_connection_t *rec);
static ngx_int_t ngx_tcp_connect(ngx_resolver_connection_t *rec);
static void ngx_resolver_cleanup(void *data);
static void ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree);
static ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r,
ngx_resolver_ctx_t *ctx, ngx_str_t *name);
static void ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree,
ngx_queue_t *queue);
static ngx_int_t ngx_resolver_send_query(ngx_resolver_t *r,
ngx_resolver_node_t *rn);
static ngx_int_t ngx_resolver_send_udp_query(ngx_resolver_t *r,
ngx_resolver_connection_t *rec, u_char *query, u_short qlen);
static ngx_int_t ngx_resolver_send_tcp_query(ngx_resolver_t *r,
ngx_resolver_connection_t *rec, u_char *query, u_short qlen);
static ngx_int_t ngx_resolver_create_name_query(ngx_resolver_t *r,
ngx_resolver_node_t *rn, ngx_str_t *name);
static ngx_int_t ngx_resolver_create_srv_query(ngx_resolver_t *r,
ngx_resolver_node_t *rn, ngx_str_t *name);
static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_t *r,
ngx_resolver_node_t *rn, ngx_resolver_addr_t *addr);
static void ngx_resolver_resend_handler(ngx_event_t *ev);
static time_t ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree,
ngx_queue_t *queue);
static ngx_uint_t ngx_resolver_resend_empty(ngx_resolver_t *r);
static void ngx_resolver_udp_read(ngx_event_t *rev);
static void ngx_resolver_tcp_write(ngx_event_t *wev);
static void ngx_resolver_tcp_read(ngx_event_t *rev);
static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf,
size_t n, ngx_uint_t tcp);
static void ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t qtype,
ngx_uint_t nan, ngx_uint_t trunc, ngx_uint_t ans);
static void ngx_resolver_process_srv(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan,
ngx_uint_t trunc, ngx_uint_t ans);
static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan);
static ngx_resolver_node_t *ngx_resolver_lookup_name(ngx_resolver_t *r,
ngx_str_t *name, uint32_t hash);
static ngx_resolver_node_t *ngx_resolver_lookup_srv(ngx_resolver_t *r,
ngx_str_t *name, uint32_t hash);
static ngx_resolver_node_t *ngx_resolver_lookup_addr(ngx_resolver_t *r,
in_addr_t addr);
static void ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
static ngx_int_t ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name,
u_char *buf, u_char *src, u_char *last);
static ngx_int_t ngx_resolver_set_timeout(ngx_resolver_t *r,
ngx_resolver_ctx_t *ctx);
static void ngx_resolver_timeout_handler(ngx_event_t *ev);
static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn);
static void *ngx_resolver_alloc(ngx_resolver_t *r, size_t size);
static void *ngx_resolver_calloc(ngx_resolver_t *r, size_t size);
static void ngx_resolver_free(ngx_resolver_t *r, void *p);
static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p);
static void *ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size);
static ngx_resolver_addr_t *ngx_resolver_export(ngx_resolver_t *r,
ngx_resolver_node_t *rn, ngx_uint_t rotate);
static void ngx_resolver_report_srv(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx);
static u_char *ngx_resolver_log_error(ngx_log_t *log, u_char *buf, size_t len);
static void ngx_resolver_resolve_srv_names(ngx_resolver_ctx_t *ctx,
ngx_resolver_node_t *rn);
static void ngx_resolver_srv_names_handler(ngx_resolver_ctx_t *ctx);
static ngx_int_t ngx_resolver_cmp_srvs(const void *one, const void *two);
#if (NGX_HAVE_INET6)
static void ngx_resolver_rbtree_insert_addr6_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
static ngx_resolver_node_t *ngx_resolver_lookup_addr6(ngx_resolver_t *r,
struct in6_addr *addr, uint32_t hash);
#endif
ngx_resolver_t *
ngx_resolver_create(ngx_conf_t *cf, ngx_str_t *names, ngx_uint_t n)
{
ngx_str_t s;
ngx_url_t u;
ngx_uint_t i, j;
ngx_resolver_t *r;
ngx_pool_cleanup_t *cln;
ngx_resolver_connection_t *rec;
r = ngx_pcalloc(cf->pool, sizeof(ngx_resolver_t));
if (r == NULL) {
return NULL;
}
r->event = ngx_pcalloc(cf->pool, sizeof(ngx_event_t));
if (r->event == NULL) {
return NULL;
}
cln = ngx_pool_cleanup_add(cf->pool, 0);
if (cln == NULL) {
return NULL;
}
cln->handler = ngx_resolver_cleanup;
cln->data = r;
ngx_rbtree_init(&r->name_rbtree, &r->name_sentinel,
ngx_resolver_rbtree_insert_value);
ngx_rbtree_init(&r->srv_rbtree, &r->srv_sentinel,
ngx_resolver_rbtree_insert_value);
ngx_rbtree_init(&r->addr_rbtree, &r->addr_sentinel,
ngx_rbtree_insert_value);
ngx_queue_init(&r->name_resend_queue);
ngx_queue_init(&r->srv_resend_queue);
ngx_queue_init(&r->addr_resend_queue);
ngx_queue_init(&r->name_expire_queue);
ngx_queue_init(&r->srv_expire_queue);
ngx_queue_init(&r->addr_expire_queue);
#if (NGX_HAVE_INET6)
r->ipv6 = 1;
ngx_rbtree_init(&r->addr6_rbtree, &r->addr6_sentinel,
ngx_resolver_rbtree_insert_addr6_value);
ngx_queue_init(&r->addr6_resend_queue);
ngx_queue_init(&r->addr6_expire_queue);
#endif
r->event->handler = ngx_resolver_resend_handler;
r->event->data = r;
r->event->log = &cf->cycle->new_log;
r->event->cancelable = 1;
r->ident = -1;
r->resend_timeout = 5;
r->tcp_timeout = 5;
r->expire = 30;
r->valid = 0;
r->log = &cf->cycle->new_log;
r->log_level = NGX_LOG_ERR;
if (n) {
if (ngx_array_init(&r->connections, cf->pool, n,
sizeof(ngx_resolver_connection_t))
!= NGX_OK)
{
return NULL;
}
}
for (i = 0; i < n; i++) {
if (ngx_strncmp(names[i].data, "valid=", 6) == 0) {
s.len = names[i].len - 6;
s.data = names[i].data + 6;
r->valid = ngx_parse_time(&s, 1);
if (r->valid == (time_t) NGX_ERROR) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter: %V", &names[i]);
return NULL;
}
continue;
}
#if (NGX_HAVE_INET6)
if (ngx_strncmp(names[i].data, "ipv6=", 5) == 0) {
if (ngx_strcmp(&names[i].data[5], "on") == 0) {
r->ipv6 = 1;
} else if (ngx_strcmp(&names[i].data[5], "off") == 0) {
r->ipv6 = 0;
} else {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter: %V", &names[i]);
return NULL;
}
continue;
}
#endif
ngx_memzero(&u, sizeof(ngx_url_t));
u.url = names[i];
u.default_port = 53;
if (ngx_parse_url(cf->pool, &u) != NGX_OK) {
if (u.err) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"%s in resolver \"%V\"",
u.err, &u.url);
}
return NULL;
}
rec = ngx_array_push_n(&r->connections, u.naddrs);
if (rec == NULL) {
return NULL;
}
ngx_memzero(rec, u.naddrs * sizeof(ngx_resolver_connection_t));
for (j = 0; j < u.naddrs; j++) {
rec[j].sockaddr = u.addrs[j].sockaddr;
rec[j].socklen = u.addrs[j].socklen;
rec[j].server = u.addrs[j].name;
rec[j].resolver = r;
}
}
if (n && r->connections.nelts == 0) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "no name servers defined");
return NULL;
}
return r;
}
static void
ngx_resolver_cleanup(void *data)
{
ngx_resolver_t *r = data;
ngx_uint_t i;
ngx_resolver_connection_t *rec;
ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "cleanup resolver");
ngx_resolver_cleanup_tree(r, &r->name_rbtree);
ngx_resolver_cleanup_tree(r, &r->srv_rbtree);
ngx_resolver_cleanup_tree(r, &r->addr_rbtree);
#if (NGX_HAVE_INET6)
ngx_resolver_cleanup_tree(r, &r->addr6_rbtree);
#endif
if (r->event->timer_set) {
ngx_del_timer(r->event);
}
rec = r->connections.elts;
for (i = 0; i < r->connections.nelts; i++) {
if (rec[i].udp) {
ngx_close_connection(rec[i].udp);
}
if (rec[i].tcp) {
ngx_close_connection(rec[i].tcp);
}
if (rec[i].read_buf) {
ngx_resolver_free(r, rec[i].read_buf->start);
ngx_resolver_free(r, rec[i].read_buf);
}
if (rec[i].write_buf) {
ngx_resolver_free(r, rec[i].write_buf->start);
ngx_resolver_free(r, rec[i].write_buf);
}
}
}
static void
ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree)
{
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_node_t *rn;
while (tree->root != tree->sentinel) {
rn = ngx_resolver_node(ngx_rbtree_min(tree->root, tree->sentinel));
ngx_queue_remove(&rn->queue);
for (ctx = rn->waiting; ctx; ctx = next) {
next = ctx->next;
if (ctx->event) {
if (ctx->event->timer_set) {
ngx_del_timer(ctx->event);
}
ngx_resolver_free(r, ctx->event);
}
ngx_resolver_free(r, ctx);
}
ngx_rbtree_delete(tree, &rn->node);
ngx_resolver_free_node(r, rn);
}
}
ngx_resolver_ctx_t *
ngx_resolve_start(ngx_resolver_t *r, ngx_resolver_ctx_t *temp)
{
in_addr_t addr;
ngx_resolver_ctx_t *ctx;
if (temp) {
addr = ngx_inet_addr(temp->name.data, temp->name.len);
if (addr != INADDR_NONE) {
temp->resolver = r;
temp->state = NGX_OK;
temp->naddrs = 1;
temp->addrs = &temp->addr;
temp->addr.sockaddr = (struct sockaddr *) &temp->sin;
temp->addr.socklen = sizeof(struct sockaddr_in);
ngx_memzero(&temp->sin, sizeof(struct sockaddr_in));
temp->sin.sin_family = AF_INET;
temp->sin.sin_addr.s_addr = addr;
temp->quick = 1;
return temp;
}
}
if (r->connections.nelts == 0) {
return NGX_NO_RESOLVER;
}
ctx = ngx_resolver_calloc(r, sizeof(ngx_resolver_ctx_t));
if (ctx) {
ctx->resolver = r;
}
return ctx;
}
ngx_int_t
ngx_resolve_name(ngx_resolver_ctx_t *ctx)
{
size_t slen;
ngx_int_t rc;
ngx_str_t name;
ngx_resolver_t *r;
r = ctx->resolver;
if (ctx->name.len > 0 && ctx->name.data[ctx->name.len - 1] == '.') {
ctx->name.len--;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve: \"%V\"", &ctx->name);
if (ctx->quick) {
ctx->handler(ctx);
return NGX_OK;
}
if (ctx->service.len) {
slen = ctx->service.len;
if (ngx_strlchr(ctx->service.data,
ctx->service.data + ctx->service.len, '.')
== NULL)
{
slen += sizeof("_._tcp") - 1;
}
name.len = slen + 1 + ctx->name.len;
name.data = ngx_resolver_alloc(r, name.len);
if (name.data == NULL) {
goto failed;
}
if (slen == ctx->service.len) {
ngx_sprintf(name.data, "%V.%V", &ctx->service, &ctx->name);
} else {
ngx_sprintf(name.data, "_%V._tcp.%V", &ctx->service, &ctx->name);
}
/* lock name mutex */
rc = ngx_resolve_name_locked(r, ctx, &name);
ngx_resolver_free(r, name.data);
} else {
/* lock name mutex */
rc = ngx_resolve_name_locked(r, ctx, &ctx->name);
}
if (rc == NGX_OK) {
return NGX_OK;
}
/* unlock name mutex */
if (rc == NGX_AGAIN) {
return NGX_OK;
}
/* NGX_ERROR */
if (ctx->event) {
ngx_resolver_free(r, ctx->event);
}
failed:
ngx_resolver_free(r, ctx);
return NGX_ERROR;
}
void
ngx_resolve_name_done(ngx_resolver_ctx_t *ctx)
{
ngx_uint_t i;
ngx_resolver_t *r;
ngx_resolver_ctx_t *w, **p;
ngx_resolver_node_t *rn;
r = ctx->resolver;
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve name done: %i", ctx->state);
if (ctx->quick) {
return;
}
if (ctx->event && ctx->event->timer_set) {
ngx_del_timer(ctx->event);
}
/* lock name mutex */
if (ctx->nsrvs) {
for (i = 0; i < ctx->nsrvs; i++) {
if (ctx->srvs[i].ctx) {
ngx_resolve_name_done(ctx->srvs[i].ctx);
}
if (ctx->srvs[i].addrs) {
ngx_resolver_free(r, ctx->srvs[i].addrs->sockaddr);
ngx_resolver_free(r, ctx->srvs[i].addrs);
}
ngx_resolver_free(r, ctx->srvs[i].name.data);
}
ngx_resolver_free(r, ctx->srvs);
}
if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
rn = ctx->node;
if (rn) {
p = &rn->waiting;
w = rn->waiting;
while (w) {
if (w == ctx) {
*p = w->next;
goto done;
}
p = &w->next;
w = w->next;
}
ngx_log_error(NGX_LOG_ALERT, r->log, 0,
"could not cancel %V resolving", &ctx->name);
}
}
done:
if (ctx->service.len) {
ngx_resolver_expire(r, &r->srv_rbtree, &r->srv_expire_queue);
} else {
ngx_resolver_expire(r, &r->name_rbtree, &r->name_expire_queue);
}
/* unlock name mutex */
/* lock alloc mutex */
if (ctx->event) {
ngx_resolver_free_locked(r, ctx->event);
}
ngx_resolver_free_locked(r, ctx);
/* unlock alloc mutex */
if (r->event->timer_set && ngx_resolver_resend_empty(r)) {
ngx_del_timer(r->event);
}
}
static ngx_int_t
ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx,
ngx_str_t *name)
{
uint32_t hash;
ngx_int_t rc;
ngx_str_t cname;
ngx_uint_t i, naddrs;
ngx_queue_t *resend_queue, *expire_queue;
ngx_rbtree_t *tree;
ngx_resolver_ctx_t *next, *last;
ngx_resolver_addr_t *addrs;
ngx_resolver_node_t *rn;
ngx_strlow(name->data, name->data, name->len);
hash = ngx_crc32_short(name->data, name->len);
if (ctx->service.len) {
rn = ngx_resolver_lookup_srv(r, name, hash);
tree = &r->srv_rbtree;
resend_queue = &r->srv_resend_queue;
expire_queue = &r->srv_expire_queue;
} else {
rn = ngx_resolver_lookup_name(r, name, hash);
tree = &r->name_rbtree;
resend_queue = &r->name_resend_queue;
expire_queue = &r->name_expire_queue;
}
if (rn) {
/* ctx can be a list after NGX_RESOLVE_CNAME */
for (last = ctx; last->next; last = last->next);
if (rn->valid >= ngx_time()) {
ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
ngx_queue_remove(&rn->queue);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(expire_queue, &rn->queue);
naddrs = (rn->naddrs == (u_short) -1) ? 0 : rn->naddrs;
#if (NGX_HAVE_INET6)
naddrs += (rn->naddrs6 == (u_short) -1) ? 0 : rn->naddrs6;
#endif
if (naddrs) {
if (naddrs == 1 && rn->naddrs == 1) {
addrs = NULL;
} else {
addrs = ngx_resolver_export(r, rn, 1);
if (addrs == NULL) {
return NGX_ERROR;
}
}
last->next = rn->waiting;
rn->waiting = NULL;
/* unlock name mutex */
do {
ctx->state = NGX_OK;
ctx->valid = rn->valid;
ctx->naddrs = naddrs;
if (addrs == NULL) {
ctx->addrs = &ctx->addr;
ctx->addr.sockaddr = (struct sockaddr *) &ctx->sin;
ctx->addr.socklen = sizeof(struct sockaddr_in);
ngx_memzero(&ctx->sin, sizeof(struct sockaddr_in));
ctx->sin.sin_family = AF_INET;
ctx->sin.sin_addr.s_addr = rn->u.addr;
} else {
ctx->addrs = addrs;
}
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
if (addrs != NULL) {
ngx_resolver_free(r, addrs->sockaddr);
ngx_resolver_free(r, addrs);
}
return NGX_OK;
}
if (rn->nsrvs) {
last->next = rn->waiting;
rn->waiting = NULL;
/* unlock name mutex */
do {
next = ctx->next;
ngx_resolver_resolve_srv_names(ctx, rn);
ctx = next;
} while (ctx);
return NGX_OK;
}
/* NGX_RESOLVE_CNAME */
if (ctx->recursion++ < NGX_RESOLVER_MAX_RECURSION) {
cname.len = rn->cnlen;
cname.data = rn->u.cname;
return ngx_resolve_name_locked(r, ctx, &cname);
}
last->next = rn->waiting;
rn->waiting = NULL;
/* unlock name mutex */
do {
ctx->state = NGX_RESOLVE_NXDOMAIN;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
return NGX_OK;
}
if (rn->waiting) {
if (ngx_resolver_set_timeout(r, ctx) != NGX_OK) {
return NGX_ERROR;
}
last->next = rn->waiting;
rn->waiting = ctx;
ctx->state = NGX_AGAIN;
ctx->async = 1;
do {
ctx->node = rn;
ctx = ctx->next;
} while (ctx);
return NGX_AGAIN;
}
ngx_queue_remove(&rn->queue);
/* lock alloc mutex */
if (rn->query) {
ngx_resolver_free_locked(r, rn->query);
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
}
if (rn->cnlen) {
ngx_resolver_free_locked(r, rn->u.cname);
}
if (rn->naddrs > 1 && rn->naddrs != (u_short) -1) {
ngx_resolver_free_locked(r, rn->u.addrs);
}
#if (NGX_HAVE_INET6)
if (rn->naddrs6 > 1 && rn->naddrs6 != (u_short) -1) {
ngx_resolver_free_locked(r, rn->u6.addrs6);
}
#endif
if (rn->nsrvs) {
for (i = 0; i < (ngx_uint_t) rn->nsrvs; i++) {
if (rn->u.srvs[i].name.data) {
ngx_resolver_free_locked(r, rn->u.srvs[i].name.data);
}
}
ngx_resolver_free_locked(r, rn->u.srvs);
}
/* unlock alloc mutex */
} else {
rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
if (rn == NULL) {
return NGX_ERROR;
}
rn->name = ngx_resolver_dup(r, name->data, name->len);
if (rn->name == NULL) {
ngx_resolver_free(r, rn);
return NGX_ERROR;
}
rn->node.key = hash;
rn->nlen = (u_short) name->len;
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
ngx_rbtree_insert(tree, &rn->node);
}
if (ctx->service.len) {
rc = ngx_resolver_create_srv_query(r, rn, name);
} else {
rc = ngx_resolver_create_name_query(r, rn, name);
}
if (rc == NGX_ERROR) {
goto failed;
}
if (rc == NGX_DECLINED) {
ngx_rbtree_delete(tree, &rn->node);
ngx_resolver_free(r, rn->query);
ngx_resolver_free(r, rn->name);
ngx_resolver_free(r, rn);
do {
ctx->state = NGX_RESOLVE_NXDOMAIN;
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
return NGX_OK;
}
rn->last_connection = r->last_connection++;
if (r->last_connection == r->connections.nelts) {
r->last_connection = 0;
}
rn->naddrs = (u_short) -1;
rn->tcp = 0;
#if (NGX_HAVE_INET6)
rn->naddrs6 = r->ipv6 ? (u_short) -1 : 0;
rn->tcp6 = 0;
#endif
rn->nsrvs = 0;
if (ngx_resolver_send_query(r, rn) != NGX_OK) {
/* immediately retry once on failure */
rn->last_connection++;
if (rn->last_connection == r->connections.nelts) {
rn->last_connection = 0;
}
(void) ngx_resolver_send_query(r, rn);
}
if (ngx_resolver_set_timeout(r, ctx) != NGX_OK) {
goto failed;
}
if (ngx_resolver_resend_empty(r)) {
ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
}
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(resend_queue, &rn->queue);
rn->code = 0;
rn->cnlen = 0;
rn->valid = 0;
rn->ttl = NGX_MAX_UINT32_VALUE;
rn->waiting = ctx;
ctx->state = NGX_AGAIN;
ctx->async = 1;
do {
ctx->node = rn;
ctx = ctx->next;
} while (ctx);
return NGX_AGAIN;
failed:
ngx_rbtree_delete(tree, &rn->node);
if (rn->query) {
ngx_resolver_free(r, rn->query);
}
ngx_resolver_free(r, rn->name);
ngx_resolver_free(r, rn);
return NGX_ERROR;
}
ngx_int_t
ngx_resolve_addr(ngx_resolver_ctx_t *ctx)
{
u_char *name;
in_addr_t addr;
ngx_queue_t *resend_queue, *expire_queue;
ngx_rbtree_t *tree;
ngx_resolver_t *r;
struct sockaddr_in *sin;
ngx_resolver_node_t *rn;
#if (NGX_HAVE_INET6)
uint32_t hash;
struct sockaddr_in6 *sin6;
#endif
#if (NGX_SUPPRESS_WARN)
addr = 0;
#if (NGX_HAVE_INET6)
hash = 0;
sin6 = NULL;
#endif
#endif
r = ctx->resolver;
switch (ctx->addr.sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
sin6 = (struct sockaddr_in6 *) ctx->addr.sockaddr;
hash = ngx_crc32_short(sin6->sin6_addr.s6_addr, 16);
/* lock addr mutex */
rn = ngx_resolver_lookup_addr6(r, &sin6->sin6_addr, hash);
tree = &r->addr6_rbtree;
resend_queue = &r->addr6_resend_queue;
expire_queue = &r->addr6_expire_queue;
break;
#endif
default: /* AF_INET */
sin = (struct sockaddr_in *) ctx->addr.sockaddr;
addr = ntohl(sin->sin_addr.s_addr);
/* lock addr mutex */
rn = ngx_resolver_lookup_addr(r, addr);
tree = &r->addr_rbtree;
resend_queue = &r->addr_resend_queue;
expire_queue = &r->addr_expire_queue;
}
if (rn) {
if (rn->valid >= ngx_time()) {
ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
ngx_queue_remove(&rn->queue);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(expire_queue, &rn->queue);
name = ngx_resolver_dup(r, rn->name, rn->nlen);
if (name == NULL) {
ngx_resolver_free(r, ctx);
return NGX_ERROR;
}
ctx->name.len = rn->nlen;
ctx->name.data = name;
/* unlock addr mutex */
ctx->state = NGX_OK;
ctx->valid = rn->valid;
ctx->handler(ctx);
ngx_resolver_free(r, name);
return NGX_OK;
}
if (rn->waiting) {
if (ngx_resolver_set_timeout(r, ctx) != NGX_OK) {
return NGX_ERROR;
}
ctx->next = rn->waiting;
rn->waiting = ctx;
ctx->state = NGX_AGAIN;
ctx->async = 1;
ctx->node = rn;
/* unlock addr mutex */
return NGX_OK;
}
ngx_queue_remove(&rn->queue);
ngx_resolver_free(r, rn->query);
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
} else {
rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
if (rn == NULL) {
goto failed;
}
switch (ctx->addr.sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
rn->addr6 = sin6->sin6_addr;
rn->node.key = hash;
break;
#endif
default: /* AF_INET */
rn->node.key = addr;
}
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
ngx_rbtree_insert(tree, &rn->node);
}
if (ngx_resolver_create_addr_query(r, rn, &ctx->addr) != NGX_OK) {
goto failed;
}
rn->last_connection = r->last_connection++;
if (r->last_connection == r->connections.nelts) {
r->last_connection = 0;
}
rn->naddrs = (u_short) -1;
rn->tcp = 0;
#if (NGX_HAVE_INET6)
rn->naddrs6 = (u_short) -1;
rn->tcp6 = 0;
#endif
rn->nsrvs = 0;
if (ngx_resolver_send_query(r, rn) != NGX_OK) {
/* immediately retry once on failure */
rn->last_connection++;
if (rn->last_connection == r->connections.nelts) {
rn->last_connection = 0;
}
(void) ngx_resolver_send_query(r, rn);
}
if (ngx_resolver_set_timeout(r, ctx) != NGX_OK) {
goto failed;
}
if (ngx_resolver_resend_empty(r)) {
ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
}
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(resend_queue, &rn->queue);
rn->code = 0;
rn->cnlen = 0;
rn->name = NULL;
rn->nlen = 0;
rn->valid = 0;
rn->ttl = NGX_MAX_UINT32_VALUE;
rn->waiting = ctx;
/* unlock addr mutex */
ctx->state = NGX_AGAIN;
ctx->async = 1;
ctx->node = rn;
return NGX_OK;
failed:
if (rn) {
ngx_rbtree_delete(tree, &rn->node);
if (rn->query) {
ngx_resolver_free(r, rn->query);
}
ngx_resolver_free(r, rn);
}
/* unlock addr mutex */
if (ctx->event) {
ngx_resolver_free(r, ctx->event);
}
ngx_resolver_free(r, ctx);
return NGX_ERROR;
}
void
ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx)
{
ngx_queue_t *expire_queue;
ngx_rbtree_t *tree;
ngx_resolver_t *r;
ngx_resolver_ctx_t *w, **p;
ngx_resolver_node_t *rn;
r = ctx->resolver;
switch (ctx->addr.sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
tree = &r->addr6_rbtree;
expire_queue = &r->addr6_expire_queue;
break;
#endif
default: /* AF_INET */
tree = &r->addr_rbtree;
expire_queue = &r->addr_expire_queue;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve addr done: %i", ctx->state);
if (ctx->event && ctx->event->timer_set) {
ngx_del_timer(ctx->event);
}
/* lock addr mutex */
if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
rn = ctx->node;
if (rn) {
p = &rn->waiting;
w = rn->waiting;
while (w) {
if (w == ctx) {
*p = w->next;
goto done;
}
p = &w->next;
w = w->next;
}
}
{
u_char text[NGX_SOCKADDR_STRLEN];
ngx_str_t addrtext;
addrtext.data = text;
addrtext.len = ngx_sock_ntop(ctx->addr.sockaddr, ctx->addr.socklen,
text, NGX_SOCKADDR_STRLEN, 0);
ngx_log_error(NGX_LOG_ALERT, r->log, 0,
"could not cancel %V resolving", &addrtext);
}
}
done:
ngx_resolver_expire(r, tree, expire_queue);
/* unlock addr mutex */
/* lock alloc mutex */
if (ctx->event) {
ngx_resolver_free_locked(r, ctx->event);
}
ngx_resolver_free_locked(r, ctx);
/* unlock alloc mutex */
if (r->event->timer_set && ngx_resolver_resend_empty(r)) {
ngx_del_timer(r->event);
}
}
static void
ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
{
time_t now;
ngx_uint_t i;
ngx_queue_t *q;
ngx_resolver_node_t *rn;
ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver expire");
now = ngx_time();
for (i = 0; i < 2; i++) {
if (ngx_queue_empty(queue)) {
return;
}
q = ngx_queue_last(queue);
rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
if (now <= rn->expire) {
return;
}
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver expire \"%*s\"", (size_t) rn->nlen, rn->name);
ngx_queue_remove(q);
ngx_rbtree_delete(tree, &rn->node);
ngx_resolver_free_node(r, rn);
}
}
static ngx_int_t
ngx_resolver_send_query(ngx_resolver_t *r, ngx_resolver_node_t *rn)
{
ngx_int_t rc;
ngx_resolver_connection_t *rec;
rec = r->connections.elts;
rec = &rec[rn->last_connection];
if (rec->log.handler == NULL) {
rec->log = *r->log;
rec->log.handler = ngx_resolver_log_error;
rec->log.data = rec;
rec->log.action = "resolving";
}
if (rn->naddrs == (u_short) -1) {
rc = rn->tcp ? ngx_resolver_send_tcp_query(r, rec, rn->query, rn->qlen)
: ngx_resolver_send_udp_query(r, rec, rn->query, rn->qlen);
if (rc != NGX_OK) {
return rc;
}
}
#if (NGX_HAVE_INET6)
if (rn->query6 && rn->naddrs6 == (u_short) -1) {
rc = rn->tcp6
? ngx_resolver_send_tcp_query(r, rec, rn->query6, rn->qlen)
: ngx_resolver_send_udp_query(r, rec, rn->query6, rn->qlen);
if (rc != NGX_OK) {
return rc;
}
}
#endif
return NGX_OK;
}
static ngx_int_t
ngx_resolver_send_udp_query(ngx_resolver_t *r, ngx_resolver_connection_t *rec,
u_char *query, u_short qlen)
{
ssize_t n;
if (rec->udp == NULL) {
if (ngx_udp_connect(rec) != NGX_OK) {
return NGX_ERROR;
}
rec->udp->data = rec;
rec->udp->read->handler = ngx_resolver_udp_read;
rec->udp->read->resolver = 1;
}
n = ngx_send(rec->udp, query, qlen);
if (n == NGX_ERROR) {
goto failed;
}
if ((size_t) n != (size_t) qlen) {
ngx_log_error(NGX_LOG_CRIT, &rec->log, 0, "send() incomplete");
goto failed;
}
return NGX_OK;
failed:
ngx_close_connection(rec->udp);
rec->udp = NULL;
return NGX_ERROR;
}
static ngx_int_t
ngx_resolver_send_tcp_query(ngx_resolver_t *r, ngx_resolver_connection_t *rec,
u_char *query, u_short qlen)
{
ngx_buf_t *b;
ngx_int_t rc;
rc = NGX_OK;
if (rec->tcp == NULL) {
b = rec->read_buf;
if (b == NULL) {
b = ngx_resolver_calloc(r, sizeof(ngx_buf_t));
if (b == NULL) {
return NGX_ERROR;
}
b->start = ngx_resolver_alloc(r, NGX_RESOLVER_TCP_RSIZE);
if (b->start == NULL) {
ngx_resolver_free(r, b);
return NGX_ERROR;
}
b->end = b->start + NGX_RESOLVER_TCP_RSIZE;
rec->read_buf = b;
}
b->pos = b->start;
b->last = b->start;
b = rec->write_buf;
if (b == NULL) {
b = ngx_resolver_calloc(r, sizeof(ngx_buf_t));
if (b == NULL) {
return NGX_ERROR;
}
b->start = ngx_resolver_alloc(r, NGX_RESOLVER_TCP_WSIZE);
if (b->start == NULL) {
ngx_resolver_free(r, b);
return NGX_ERROR;
}
b->end = b->start + NGX_RESOLVER_TCP_WSIZE;
rec->write_buf = b;
}
b->pos = b->start;
b->last = b->start;
rc = ngx_tcp_connect(rec);
if (rc == NGX_ERROR) {
return NGX_ERROR;
}
rec->tcp->data = rec;
rec->tcp->write->handler = ngx_resolver_tcp_write;
rec->tcp->write->cancelable = 1;
rec->tcp->read->handler = ngx_resolver_tcp_read;
rec->tcp->read->resolver = 1;
ngx_add_timer(rec->tcp->write, (ngx_msec_t) (r->tcp_timeout * 1000));
}
b = rec->write_buf;
if (b->end - b->last < 2 + qlen) {
ngx_log_error(NGX_LOG_CRIT, &rec->log, 0, "buffer overflow");
return NGX_ERROR;
}
*b->last++ = (u_char) (qlen >> 8);
*b->last++ = (u_char) qlen;
b->last = ngx_cpymem(b->last, query, qlen);
if (rc == NGX_OK) {
ngx_resolver_tcp_write(rec->tcp->write);
}
return NGX_OK;
}
static void
ngx_resolver_resend_handler(ngx_event_t *ev)
{
time_t timer, atimer, stimer, ntimer;
#if (NGX_HAVE_INET6)
time_t a6timer;
#endif
ngx_resolver_t *r;
r = ev->data;
ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver resend handler");
/* lock name mutex */
ntimer = ngx_resolver_resend(r, &r->name_rbtree, &r->name_resend_queue);
stimer = ngx_resolver_resend(r, &r->srv_rbtree, &r->srv_resend_queue);
/* unlock name mutex */
/* lock addr mutex */
atimer = ngx_resolver_resend(r, &r->addr_rbtree, &r->addr_resend_queue);
/* unlock addr mutex */
#if (NGX_HAVE_INET6)
/* lock addr6 mutex */
a6timer = ngx_resolver_resend(r, &r->addr6_rbtree, &r->addr6_resend_queue);
/* unlock addr6 mutex */
#endif
timer = ntimer;
if (timer == 0) {
timer = atimer;
} else if (atimer) {
timer = ngx_min(timer, atimer);
}
if (timer == 0) {
timer = stimer;
} else if (stimer) {
timer = ngx_min(timer, stimer);
}
#if (NGX_HAVE_INET6)
if (timer == 0) {
timer = a6timer;
} else if (a6timer) {
timer = ngx_min(timer, a6timer);
}
#endif
if (timer) {
ngx_add_timer(r->event, (ngx_msec_t) (timer * 1000));
}
}
static time_t
ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
{
time_t now;
ngx_queue_t *q;
ngx_resolver_node_t *rn;
now = ngx_time();
for ( ;; ) {
if (ngx_queue_empty(queue)) {
return 0;
}
q = ngx_queue_last(queue);
rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
if (now < rn->expire) {
return rn->expire - now;
}
ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver resend \"%*s\" %p",
(size_t) rn->nlen, rn->name, rn->waiting);
ngx_queue_remove(q);
if (rn->waiting) {
if (++rn->last_connection == r->connections.nelts) {
rn->last_connection = 0;
}
(void) ngx_resolver_send_query(r, rn);
rn->expire = now + r->resend_timeout;
ngx_queue_insert_head(queue, q);
continue;
}
ngx_rbtree_delete(tree, &rn->node);
ngx_resolver_free_node(r, rn);
}
}
static ngx_uint_t
ngx_resolver_resend_empty(ngx_resolver_t *r)
{
return ngx_queue_empty(&r->name_resend_queue)
&& ngx_queue_empty(&r->srv_resend_queue)
#if (NGX_HAVE_INET6)
&& ngx_queue_empty(&r->addr6_resend_queue)
#endif
&& ngx_queue_empty(&r->addr_resend_queue);
}
static void
ngx_resolver_udp_read(ngx_event_t *rev)
{
ssize_t n;
ngx_connection_t *c;
ngx_resolver_connection_t *rec;
u_char buf[NGX_RESOLVER_UDP_SIZE];
c = rev->data;
rec = c->data;
do {
n = ngx_udp_recv(c, buf, NGX_RESOLVER_UDP_SIZE);
if (n == NGX_AGAIN) {
break;
}
if (n == NGX_ERROR) {
goto failed;
}
ngx_resolver_process_response(rec->resolver, buf, n, 0);
} while (rev->ready);
if (ngx_handle_read_event(rev, 0) != NGX_OK) {
goto failed;
}
return;
failed:
ngx_close_connection(rec->udp);
rec->udp = NULL;
}
static void
ngx_resolver_tcp_write(ngx_event_t *wev)
{
off_t sent;
ssize_t n;
ngx_buf_t *b;
ngx_resolver_t *r;
ngx_connection_t *c;
ngx_resolver_connection_t *rec;
c = wev->data;
rec = c->data;
b = rec->write_buf;
r = rec->resolver;
if (wev->timedout) {
goto failed;
}
sent = c->sent;
while (wev->ready && b->pos < b->last) {
n = ngx_send(c, b->pos, b->last - b->pos);
if (n == NGX_AGAIN) {
break;
}
if (n == NGX_ERROR) {
goto failed;
}
b->pos += n;
}
if (b->pos != b->start) {
b->last = ngx_movemem(b->start, b->pos, b->last - b->pos);
b->pos = b->start;
}
if (c->sent != sent) {
ngx_add_timer(wev, (ngx_msec_t) (r->tcp_timeout * 1000));
}
if (ngx_handle_write_event(wev, 0) != NGX_OK) {
goto failed;
}
return;
failed:
ngx_close_connection(c);
rec->tcp = NULL;
}
static void
ngx_resolver_tcp_read(ngx_event_t *rev)
{
u_char *p;
size_t size;
ssize_t n;
u_short qlen;
ngx_buf_t *b;
ngx_resolver_t *r;
ngx_connection_t *c;
ngx_resolver_connection_t *rec;
c = rev->data;
rec = c->data;
b = rec->read_buf;
r = rec->resolver;
while (rev->ready) {
n = ngx_recv(c, b->last, b->end - b->last);
if (n == NGX_AGAIN) {
break;
}
if (n == NGX_ERROR || n == 0) {
goto failed;
}
b->last += n;
for ( ;; ) {
p = b->pos;
size = b->last - p;
if (size < 2) {
break;
}
qlen = (u_short) *p++ << 8;
qlen += *p++;
if (size < (size_t) (2 + qlen)) {
break;
}
ngx_resolver_process_response(r, p, qlen, 1);
b->pos += 2 + qlen;
}
if (b->pos != b->start) {
b->last = ngx_movemem(b->start, b->pos, b->last - b->pos);
b->pos = b->start;
}
}
if (ngx_handle_read_event(rev, 0) != NGX_OK) {
goto failed;
}
return;
failed:
ngx_close_connection(c);
rec->tcp = NULL;
}
static void
ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t tcp)
{
char *err;
ngx_uint_t i, times, ident, qident, flags, code, nqs, nan, trunc,
qtype, qclass;
#if (NGX_HAVE_INET6)
ngx_uint_t qident6;
#endif
ngx_queue_t *q;
ngx_resolver_qs_t *qs;
ngx_resolver_hdr_t *response;
ngx_resolver_node_t *rn;
if (n < sizeof(ngx_resolver_hdr_t)) {
goto short_response;
}
response = (ngx_resolver_hdr_t *) buf;
ident = (response->ident_hi << 8) + response->ident_lo;
flags = (response->flags_hi << 8) + response->flags_lo;
nqs = (response->nqs_hi << 8) + response->nqs_lo;
nan = (response->nan_hi << 8) + response->nan_lo;
trunc = flags & 0x0200;
ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver DNS response %ui fl:%04Xi %ui/%ui/%ud/%ud",
ident, flags, nqs, nan,
(response->nns_hi << 8) + response->nns_lo,
(response->nar_hi << 8) + response->nar_lo);
/* response to a standard query */
if ((flags & 0xf870) != 0x8000 || (trunc && tcp)) {
ngx_log_error(r->log_level, r->log, 0,
"invalid %s DNS response %ui fl:%04Xi",
tcp ? "TCP" : "UDP", ident, flags);
return;
}
code = flags & 0xf;
if (code == NGX_RESOLVE_FORMERR) {
times = 0;
for (q = ngx_queue_head(&r->name_resend_queue);
q != ngx_queue_sentinel(&r->name_resend_queue) && times++ < 100;
q = ngx_queue_next(q))
{
rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
qident = (rn->query[0] << 8) + rn->query[1];
if (qident == ident) {
goto dns_error_name;
}
#if (NGX_HAVE_INET6)
if (rn->query6) {
qident6 = (rn->query6[0] << 8) + rn->query6[1];
if (qident6 == ident) {
goto dns_error_name;
}
}
#endif
}
goto dns_error;
}
if (code > NGX_RESOLVE_REFUSED) {
goto dns_error;
}
if (nqs != 1) {
err = "invalid number of questions in DNS response";
goto done;
}
i = sizeof(ngx_resolver_hdr_t);
while (i < (ngx_uint_t) n) {
if (buf[i] & 0xc0) {
err = "unexpected compression pointer in DNS response";
goto done;
}
if (buf[i] == '\0') {
goto found;
}
i += 1 + buf[i];
}
goto short_response;
found:
if (i++ == sizeof(ngx_resolver_hdr_t)) {
err = "zero-length domain name in DNS response";
goto done;
}
if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t))
> (ngx_uint_t) n)
{
goto short_response;
}
qs = (ngx_resolver_qs_t *) &buf[i];
qtype = (qs->type_hi << 8) + qs->type_lo;
qclass = (qs->class_hi << 8) + qs->class_lo;
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver DNS response qt:%ui cl:%ui", qtype, qclass);
if (qclass != 1) {
ngx_log_error(r->log_level, r->log, 0,
"unknown query class %ui in DNS response", qclass);
return;
}
switch (qtype) {
case NGX_RESOLVE_A:
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
#endif
ngx_resolver_process_a(r, buf, n, ident, code, qtype, nan, trunc,
i + sizeof(ngx_resolver_qs_t));
break;
case NGX_RESOLVE_SRV:
ngx_resolver_process_srv(r, buf, n, ident, code, nan, trunc,
i + sizeof(ngx_resolver_qs_t));
break;
case NGX_RESOLVE_PTR:
ngx_resolver_process_ptr(r, buf, n, ident, code, nan);
break;
default:
ngx_log_error(r->log_level, r->log, 0,
"unknown query type %ui in DNS response", qtype);
return;
}
return;
short_response:
err = "short DNS response";
done:
ngx_log_error(r->log_level, r->log, 0, err);
return;
dns_error_name:
ngx_log_error(r->log_level, r->log, 0,
"DNS error (%ui: %s), query id:%ui, name:\"%*s\"",
code, ngx_resolver_strerror(code), ident,
(size_t) rn->nlen, rn->name);
return;
dns_error:
ngx_log_error(r->log_level, r->log, 0,
"DNS error (%ui: %s), query id:%ui",
code, ngx_resolver_strerror(code), ident);
return;
}
static void
ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t qtype,
ngx_uint_t nan, ngx_uint_t trunc, ngx_uint_t ans)
{
char *err;
u_char *cname;
size_t len;
int32_t ttl;
uint32_t hash;
in_addr_t *addr;
ngx_str_t name;
ngx_uint_t type, class, qident, naddrs, a, i, j, start;
#if (NGX_HAVE_INET6)
struct in6_addr *addr6;
#endif
ngx_resolver_an_t *an;
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_node_t *rn;
ngx_resolver_addr_t *addrs;
ngx_resolver_connection_t *rec;
if (ngx_resolver_copy(r, &name, buf,
buf + sizeof(ngx_resolver_hdr_t), buf + n)
!= NGX_OK)
{
return;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name);
hash = ngx_crc32_short(name.data, name.len);
/* lock name mutex */
rn = ngx_resolver_lookup_name(r, &name, hash);
if (rn == NULL) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected DNS response for %V", &name);
ngx_resolver_free(r, name.data);
goto failed;
}
switch (qtype) {
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
if (rn->query6 == NULL || rn->naddrs6 != (u_short) -1) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected DNS response for %V", &name);
ngx_resolver_free(r, name.data);
goto failed;
}
if (trunc && rn->tcp6) {
ngx_resolver_free(r, name.data);
goto failed;
}
qident = (rn->query6[0] << 8) + rn->query6[1];
break;
#endif
default: /* NGX_RESOLVE_A */
if (rn->query == NULL || rn->naddrs != (u_short) -1) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected DNS response for %V", &name);
ngx_resolver_free(r, name.data);
goto failed;
}
if (trunc && rn->tcp) {
ngx_resolver_free(r, name.data);
goto failed;
}
qident = (rn->query[0] << 8) + rn->query[1];
}
if (ident != qident) {
ngx_log_error(r->log_level, r->log, 0,
"wrong ident %ui in DNS response for %V, expect %ui",
ident, &name, qident);
ngx_resolver_free(r, name.data);
goto failed;
}
ngx_resolver_free(r, name.data);
if (trunc) {
ngx_queue_remove(&rn->queue);
if (rn->waiting == NULL) {
ngx_rbtree_delete(&r->name_rbtree, &rn->node);
ngx_resolver_free_node(r, rn);
goto next;
}
rec = r->connections.elts;
rec = &rec[rn->last_connection];
switch (qtype) {
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
rn->tcp6 = 1;
(void) ngx_resolver_send_tcp_query(r, rec, rn->query6, rn->qlen);
break;
#endif
default: /* NGX_RESOLVE_A */
rn->tcp = 1;
(void) ngx_resolver_send_tcp_query(r, rec, rn->query, rn->qlen);
}
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(&r->name_resend_queue, &rn->queue);
goto next;
}
if (code == 0 && rn->code) {
code = rn->code;
}
if (code == 0 && nan == 0) {
#if (NGX_HAVE_INET6)
switch (qtype) {
case NGX_RESOLVE_AAAA:
rn->naddrs6 = 0;
if (rn->naddrs == (u_short) -1) {
goto next;
}
if (rn->naddrs) {
goto export;
}
break;
default: /* NGX_RESOLVE_A */
rn->naddrs = 0;
if (rn->naddrs6 == (u_short) -1) {
goto next;
}
if (rn->naddrs6) {
goto export;
}
}
#endif
code = NGX_RESOLVE_NXDOMAIN;
}
if (code) {
#if (NGX_HAVE_INET6)
switch (qtype) {
case NGX_RESOLVE_AAAA:
rn->naddrs6 = 0;
if (rn->naddrs == (u_short) -1) {
rn->code = (u_char) code;
goto next;
}
break;
default: /* NGX_RESOLVE_A */
rn->naddrs = 0;
if (rn->naddrs6 == (u_short) -1) {
rn->code = (u_char) code;
goto next;
}
}
#endif
next = rn->waiting;
rn->waiting = NULL;
ngx_queue_remove(&rn->queue);
ngx_rbtree_delete(&r->name_rbtree, &rn->node);
/* unlock name mutex */
while (next) {
ctx = next;
ctx->state = code;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
next = ctx->next;
ctx->handler(ctx);
}
ngx_resolver_free_node(r, rn);
return;
}
i = ans;
naddrs = 0;
cname = NULL;
for (a = 0; a < nan; a++) {
start = i;
while (i < n) {
if (buf[i] & 0xc0) {
i += 2;
goto found;
}
if (buf[i] == 0) {
i++;
goto test_length;
}
i += 1 + buf[i];
}
goto short_response;
test_length:
if (i - start < 2) {
err = "invalid name in DNS response";
goto invalid;
}
found:
if (i + sizeof(ngx_resolver_an_t) >= n) {
goto short_response;
}
an = (ngx_resolver_an_t *) &buf[i];
type = (an->type_hi << 8) + an->type_lo;
class = (an->class_hi << 8) + an->class_lo;
len = (an->len_hi << 8) + an->len_lo;
ttl = (an->ttl[0] << 24) + (an->ttl[1] << 16)
+ (an->ttl[2] << 8) + (an->ttl[3]);
if (class != 1) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR class %ui in DNS response", class);
goto failed;
}
if (ttl < 0) {
ttl = 0;
}
rn->ttl = ngx_min(rn->ttl, (uint32_t) ttl);
i += sizeof(ngx_resolver_an_t);
switch (type) {
case NGX_RESOLVE_A:
if (qtype != NGX_RESOLVE_A) {
err = "unexpected A record in DNS response";
goto invalid;
}
if (len != 4) {
err = "invalid A record in DNS response";
goto invalid;
}
if (i + 4 > n) {
goto short_response;
}
naddrs++;
break;
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
if (qtype != NGX_RESOLVE_AAAA) {
err = "unexpected AAAA record in DNS response";
goto invalid;
}
if (len != 16) {
err = "invalid AAAA record in DNS response";
goto invalid;
}
if (i + 16 > n) {
goto short_response;
}
naddrs++;
break;
#endif
case NGX_RESOLVE_CNAME:
cname = &buf[i];
break;
case NGX_RESOLVE_DNAME:
break;
default:
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR type %ui in DNS response", type);
}
i += len;
}
ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver naddrs:%ui cname:%p ttl:%uD",
naddrs, cname, rn->ttl);
if (naddrs) {
switch (qtype) {
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
if (naddrs == 1) {
addr6 = &rn->u6.addr6;
rn->naddrs6 = 1;
} else {
addr6 = ngx_resolver_alloc(r, naddrs * sizeof(struct in6_addr));
if (addr6 == NULL) {
goto failed;
}
rn->u6.addrs6 = addr6;
rn->naddrs6 = (u_short) naddrs;
}
#if (NGX_SUPPRESS_WARN)
addr = NULL;
#endif
break;
#endif
default: /* NGX_RESOLVE_A */
if (naddrs == 1) {
addr = &rn->u.addr;
rn->naddrs = 1;
} else {
addr = ngx_resolver_alloc(r, naddrs * sizeof(in_addr_t));
if (addr == NULL) {
goto failed;
}
rn->u.addrs = addr;
rn->naddrs = (u_short) naddrs;
}
#if (NGX_HAVE_INET6 && NGX_SUPPRESS_WARN)
addr6 = NULL;
#endif
}
j = 0;
i = ans;
for (a = 0; a < nan; a++) {
for ( ;; ) {
if (buf[i] & 0xc0) {
i += 2;
break;
}
if (buf[i] == 0) {
i++;
break;
}
i += 1 + buf[i];
}
an = (ngx_resolver_an_t *) &buf[i];
type = (an->type_hi << 8) + an->type_lo;
len = (an->len_hi << 8) + an->len_lo;
i += sizeof(ngx_resolver_an_t);
if (type == NGX_RESOLVE_A) {
addr[j] = htonl((buf[i] << 24) + (buf[i + 1] << 16)
+ (buf[i + 2] << 8) + (buf[i + 3]));
if (++j == naddrs) {
#if (NGX_HAVE_INET6)
if (rn->naddrs6 == (u_short) -1) {
goto next;
}
#endif
break;
}
}
#if (NGX_HAVE_INET6)
else if (type == NGX_RESOLVE_AAAA) {
ngx_memcpy(addr6[j].s6_addr, &buf[i], 16);
if (++j == naddrs) {
if (rn->naddrs == (u_short) -1) {
goto next;
}
break;
}
}
#endif
i += len;
}
}
switch (qtype) {
#if (NGX_HAVE_INET6)
case NGX_RESOLVE_AAAA:
if (rn->naddrs6 == (u_short) -1) {
rn->naddrs6 = 0;
}
break;
#endif
default: /* NGX_RESOLVE_A */
if (rn->naddrs == (u_short) -1) {
rn->naddrs = 0;
}
}
if (rn->naddrs != (u_short) -1
#if (NGX_HAVE_INET6)
&& rn->naddrs6 != (u_short) -1
#endif
&& rn->naddrs
#if (NGX_HAVE_INET6)
+ rn->naddrs6
#endif
> 0)
{
#if (NGX_HAVE_INET6)
export:
#endif
naddrs = rn->naddrs;
#if (NGX_HAVE_INET6)
naddrs += rn->naddrs6;
#endif
if (naddrs == 1 && rn->naddrs == 1) {
addrs = NULL;
} else {
addrs = ngx_resolver_export(r, rn, 0);
if (addrs == NULL) {
goto failed;
}
}
ngx_queue_remove(&rn->queue);
rn->valid = ngx_time() + (r->valid ? r->valid : (time_t) rn->ttl);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
next = rn->waiting;
rn->waiting = NULL;
/* unlock name mutex */
while (next) {
ctx = next;
ctx->state = NGX_OK;
ctx->valid = rn->valid;
ctx->naddrs = naddrs;
if (addrs == NULL) {
ctx->addrs = &ctx->addr;
ctx->addr.sockaddr = (struct sockaddr *) &ctx->sin;
ctx->addr.socklen = sizeof(struct sockaddr_in);
ngx_memzero(&ctx->sin, sizeof(struct sockaddr_in));
ctx->sin.sin_family = AF_INET;
ctx->sin.sin_addr.s_addr = rn->u.addr;
} else {
ctx->addrs = addrs;
}
next = ctx->next;
ctx->handler(ctx);
}
if (addrs != NULL) {
ngx_resolver_free(r, addrs->sockaddr);
ngx_resolver_free(r, addrs);
}
ngx_resolver_free(r, rn->query);
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
return;
}
if (cname) {
/* CNAME only */
if (rn->naddrs == (u_short) -1
#if (NGX_HAVE_INET6)
|| rn->naddrs6 == (u_short) -1
#endif
)
{
goto next;
}
if (ngx_resolver_copy(r, &name, buf, cname, buf + n) != NGX_OK) {
goto failed;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver cname:\"%V\"", &name);
ngx_queue_remove(&rn->queue);
rn->cnlen = (u_short) name.len;
rn->u.cname = name.data;
rn->valid = ngx_time() + (r->valid ? r->valid : (time_t) rn->ttl);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
ngx_resolver_free(r, rn->query);
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
ctx = rn->waiting;
rn->waiting = NULL;
if (ctx) {
if (ctx->recursion++ >= NGX_RESOLVER_MAX_RECURSION) {
/* unlock name mutex */
do {
ctx->state = NGX_RESOLVE_NXDOMAIN;
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
return;
}
for (next = ctx; next; next = next->next) {
next->node = NULL;
}
(void) ngx_resolve_name_locked(r, ctx, &name);
}
/* unlock name mutex */
return;
}
ngx_log_error(r->log_level, r->log, 0,
"no A or CNAME types in DNS response");
return;
short_response:
err = "short DNS response";
invalid:
/* unlock name mutex */
ngx_log_error(r->log_level, r->log, 0, err);
return;
failed:
next:
/* unlock name mutex */
return;
}
static void
ngx_resolver_process_srv(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan,
ngx_uint_t trunc, ngx_uint_t ans)
{
char *err;
u_char *cname;
size_t len;
int32_t ttl;
uint32_t hash;
ngx_str_t name;
ngx_uint_t type, qident, class, start, nsrvs, a, i, j;
ngx_resolver_an_t *an;
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_srv_t *srvs;
ngx_resolver_node_t *rn;
ngx_resolver_connection_t *rec;
if (ngx_resolver_copy(r, &name, buf,
buf + sizeof(ngx_resolver_hdr_t), buf + n)
!= NGX_OK)
{
return;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name);
hash = ngx_crc32_short(name.data, name.len);
rn = ngx_resolver_lookup_srv(r, &name, hash);
if (rn == NULL || rn->query == NULL) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected DNS response for %V", &name);
ngx_resolver_free(r, name.data);
goto failed;
}
if (trunc && rn->tcp) {
ngx_resolver_free(r, name.data);
goto failed;
}
qident = (rn->query[0] << 8) + rn->query[1];
if (ident != qident) {
ngx_log_error(r->log_level, r->log, 0,
"wrong ident %ui in DNS response for %V, expect %ui",
ident, &name, qident);
ngx_resolver_free(r, name.data);
goto failed;
}
ngx_resolver_free(r, name.data);
if (trunc) {
ngx_queue_remove(&rn->queue);
if (rn->waiting == NULL) {
ngx_rbtree_delete(&r->srv_rbtree, &rn->node);
ngx_resolver_free_node(r, rn);
return;
}
rec = r->connections.elts;
rec = &rec[rn->last_connection];
rn->tcp = 1;
(void) ngx_resolver_send_tcp_query(r, rec, rn->query, rn->qlen);
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(&r->srv_resend_queue, &rn->queue);
return;
}
if (code == 0 && rn->code) {
code = rn->code;
}
if (code == 0 && nan == 0) {
code = NGX_RESOLVE_NXDOMAIN;
}
if (code) {
next = rn->waiting;
rn->waiting = NULL;
ngx_queue_remove(&rn->queue);
ngx_rbtree_delete(&r->srv_rbtree, &rn->node);
while (next) {
ctx = next;
ctx->state = code;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
next = ctx->next;
ctx->handler(ctx);
}
ngx_resolver_free_node(r, rn);
return;
}
i = ans;
nsrvs = 0;
cname = NULL;
for (a = 0; a < nan; a++) {
start = i;
while (i < n) {
if (buf[i] & 0xc0) {
i += 2;
goto found;
}
if (buf[i] == 0) {
i++;
goto test_length;
}
i += 1 + buf[i];
}
goto short_response;
test_length:
if (i - start < 2) {
err = "invalid name DNS response";
goto invalid;
}
found:
if (i + sizeof(ngx_resolver_an_t) >= n) {
goto short_response;
}
an = (ngx_resolver_an_t *) &buf[i];
type = (an->type_hi << 8) + an->type_lo;
class = (an->class_hi << 8) + an->class_lo;
len = (an->len_hi << 8) + an->len_lo;
ttl = (an->ttl[0] << 24) + (an->ttl[1] << 16)
+ (an->ttl[2] << 8) + (an->ttl[3]);
if (class != 1) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR class %ui in DNS response", class);
goto failed;
}
if (ttl < 0) {
ttl = 0;
}
rn->ttl = ngx_min(rn->ttl, (uint32_t) ttl);
i += sizeof(ngx_resolver_an_t);
switch (type) {
case NGX_RESOLVE_SRV:
if (i + 6 > n) {
goto short_response;
}
if (ngx_resolver_copy(r, NULL, buf, &buf[i + 6], buf + n)
!= NGX_OK)
{
goto failed;
}
nsrvs++;
break;
case NGX_RESOLVE_CNAME:
cname = &buf[i];
break;
case NGX_RESOLVE_DNAME:
break;
default:
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR type %ui in DNS response", type);
}
i += len;
}
ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver nsrvs:%ui cname:%p ttl:%uD",
nsrvs, cname, rn->ttl);
if (nsrvs) {
srvs = ngx_resolver_calloc(r, nsrvs * sizeof(ngx_resolver_srv_t));
if (srvs == NULL) {
goto failed;
}
rn->u.srvs = srvs;
rn->nsrvs = (u_short) nsrvs;
j = 0;
i = ans;
for (a = 0; a < nan; a++) {
for ( ;; ) {
if (buf[i] & 0xc0) {
i += 2;
break;
}
if (buf[i] == 0) {
i++;
break;
}
i += 1 + buf[i];
}
an = (ngx_resolver_an_t *) &buf[i];
type = (an->type_hi << 8) + an->type_lo;
len = (an->len_hi << 8) + an->len_lo;
i += sizeof(ngx_resolver_an_t);
if (type == NGX_RESOLVE_SRV) {
srvs[j].priority = (buf[i] << 8) + buf[i + 1];
srvs[j].weight = (buf[i + 2] << 8) + buf[i + 3];
if (srvs[j].weight == 0) {
srvs[j].weight = 1;
}
srvs[j].port = (buf[i + 4] << 8) + buf[i + 5];
if (ngx_resolver_copy(r, &srvs[j].name, buf, &buf[i + 6],
buf + n)
!= NGX_OK)
{
goto failed;
}
j++;
}
i += len;
}
ngx_sort(srvs, nsrvs, sizeof(ngx_resolver_srv_t),
ngx_resolver_cmp_srvs);
ngx_resolver_free(r, rn->query);
rn->query = NULL;
ngx_queue_remove(&rn->queue);
rn->valid = ngx_time() + (r->valid ? r->valid : (time_t) rn->ttl);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->srv_expire_queue, &rn->queue);
next = rn->waiting;
rn->waiting = NULL;
while (next) {
ctx = next;
next = ctx->next;
ngx_resolver_resolve_srv_names(ctx, rn);
}
return;
}
rn->nsrvs = 0;
if (cname) {
/* CNAME only */
if (ngx_resolver_copy(r, &name, buf, cname, buf + n) != NGX_OK) {
goto failed;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver cname:\"%V\"", &name);
ngx_queue_remove(&rn->queue);
rn->cnlen = (u_short) name.len;
rn->u.cname = name.data;
rn->valid = ngx_time() + (r->valid ? r->valid : (time_t) rn->ttl);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->srv_expire_queue, &rn->queue);
ngx_resolver_free(r, rn->query);
rn->query = NULL;
#if (NGX_HAVE_INET6)
rn->query6 = NULL;
#endif
ctx = rn->waiting;
rn->waiting = NULL;
if (ctx) {
if (ctx->recursion++ >= NGX_RESOLVER_MAX_RECURSION) {
/* unlock name mutex */
do {
ctx->state = NGX_RESOLVE_NXDOMAIN;
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
return;
}
for (next = ctx; next; next = next->next) {
next->node = NULL;
}
(void) ngx_resolve_name_locked(r, ctx, &name);
}
/* unlock name mutex */
return;
}
ngx_log_error(r->log_level, r->log, 0, "no SRV type in DNS response");
return;
short_response:
err = "short DNS response";
invalid:
/* unlock name mutex */
ngx_log_error(r->log_level, r->log, 0, err);
return;
failed:
/* unlock name mutex */
return;
}
static void
ngx_resolver_resolve_srv_names(ngx_resolver_ctx_t *ctx, ngx_resolver_node_t *rn)
{
ngx_uint_t i;
ngx_resolver_t *r;
ngx_resolver_ctx_t *cctx;
ngx_resolver_srv_name_t *srvs;
r = ctx->resolver;
ctx->node = NULL;
ctx->state = NGX_OK;
ctx->valid = rn->valid;
ctx->count = rn->nsrvs;
srvs = ngx_resolver_calloc(r, rn->nsrvs * sizeof(ngx_resolver_srv_name_t));
if (srvs == NULL) {
goto failed;
}
ctx->srvs = srvs;
ctx->nsrvs = rn->nsrvs;
if (ctx->event && ctx->event->timer_set) {
ngx_del_timer(ctx->event);
}
for (i = 0; i < (ngx_uint_t) rn->nsrvs; i++) {
srvs[i].name.data = ngx_resolver_alloc(r, rn->u.srvs[i].name.len);
if (srvs[i].name.data == NULL) {
goto failed;
}
srvs[i].name.len = rn->u.srvs[i].name.len;
ngx_memcpy(srvs[i].name.data, rn->u.srvs[i].name.data,
srvs[i].name.len);
cctx = ngx_resolve_start(r, NULL);
if (cctx == NULL) {
goto failed;
}
cctx->name = srvs[i].name;
cctx->handler = ngx_resolver_srv_names_handler;
cctx->data = ctx;
cctx->srvs = &srvs[i];
cctx->timeout = ctx->timeout;
srvs[i].priority = rn->u.srvs[i].priority;
srvs[i].weight = rn->u.srvs[i].weight;
srvs[i].port = rn->u.srvs[i].port;
srvs[i].ctx = cctx;
if (ngx_resolve_name(cctx) == NGX_ERROR) {
srvs[i].ctx = NULL;
goto failed;
}
}
return;
failed:
ctx->state = NGX_ERROR;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
ctx->handler(ctx);
}
static void
ngx_resolver_srv_names_handler(ngx_resolver_ctx_t *cctx)
{
ngx_uint_t i;
ngx_addr_t *addrs;
ngx_resolver_t *r;
ngx_sockaddr_t *sockaddr;
ngx_resolver_ctx_t *ctx;
ngx_resolver_srv_name_t *srv;
r = cctx->resolver;
ctx = cctx->data;
srv = cctx->srvs;
ctx->count--;
ctx->async |= cctx->async;
srv->ctx = NULL;
srv->state = cctx->state;
if (cctx->naddrs) {
ctx->valid = ngx_min(ctx->valid, cctx->valid);
addrs = ngx_resolver_calloc(r, cctx->naddrs * sizeof(ngx_addr_t));
if (addrs == NULL) {
srv->state = NGX_ERROR;
goto done;
}
sockaddr = ngx_resolver_alloc(r, cctx->naddrs * sizeof(ngx_sockaddr_t));
if (sockaddr == NULL) {
ngx_resolver_free(r, addrs);
srv->state = NGX_ERROR;
goto done;
}
for (i = 0; i < cctx->naddrs; i++) {
addrs[i].sockaddr = &sockaddr[i].sockaddr;
addrs[i].socklen = cctx->addrs[i].socklen;
ngx_memcpy(&sockaddr[i], cctx->addrs[i].sockaddr,
addrs[i].socklen);
ngx_inet_set_port(addrs[i].sockaddr, srv->port);
}
srv->addrs = addrs;
srv->naddrs = cctx->naddrs;
}
done:
ngx_resolve_name_done(cctx);
if (ctx->count == 0) {
ngx_resolver_report_srv(r, ctx);
}
}
static void
ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan)
{
char *err;
size_t len;
in_addr_t addr;
int32_t ttl;
ngx_int_t octet;
ngx_str_t name;
ngx_uint_t mask, type, class, qident, a, i, start;
ngx_queue_t *expire_queue;
ngx_rbtree_t *tree;
ngx_resolver_an_t *an;
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_node_t *rn;
#if (NGX_HAVE_INET6)
uint32_t hash;
ngx_int_t digit;
struct in6_addr addr6;
#endif
if (ngx_resolver_copy(r, &name, buf,
buf + sizeof(ngx_resolver_hdr_t), buf + n)
!= NGX_OK)
{
return;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name);
/* AF_INET */
addr = 0;
i = sizeof(ngx_resolver_hdr_t);
for (mask = 0; mask < 32; mask += 8) {
len = buf[i++];
octet = ngx_atoi(&buf[i], len);
if (octet == NGX_ERROR || octet > 255) {
goto invalid_in_addr_arpa;
}
addr += octet << mask;
i += len;
}
if (ngx_strcasecmp(&buf[i], (u_char *) "\7in-addr\4arpa") == 0) {
i += sizeof("\7in-addr\4arpa");
/* lock addr mutex */
rn = ngx_resolver_lookup_addr(r, addr);
tree = &r->addr_rbtree;
expire_queue = &r->addr_expire_queue;
goto valid;
}
invalid_in_addr_arpa:
#if (NGX_HAVE_INET6)
i = sizeof(ngx_resolver_hdr_t);
for (octet = 15; octet >= 0; octet--) {
if (buf[i++] != '\1') {
goto invalid_ip6_arpa;
}
digit = ngx_hextoi(&buf[i++], 1);
if (digit == NGX_ERROR) {
goto invalid_ip6_arpa;
}
addr6.s6_addr[octet] = (u_char) digit;
if (buf[i++] != '\1') {
goto invalid_ip6_arpa;
}
digit = ngx_hextoi(&buf[i++], 1);
if (digit == NGX_ERROR) {
goto invalid_ip6_arpa;
}
addr6.s6_addr[octet] += (u_char) (digit * 16);
}
if (ngx_strcasecmp(&buf[i], (u_char *) "\3ip6\4arpa") == 0) {
i += sizeof("\3ip6\4arpa");
/* lock addr mutex */
hash = ngx_crc32_short(addr6.s6_addr, 16);
rn = ngx_resolver_lookup_addr6(r, &addr6, hash);
tree = &r->addr6_rbtree;
expire_queue = &r->addr6_expire_queue;
goto valid;
}
invalid_ip6_arpa:
#endif
ngx_log_error(r->log_level, r->log, 0,
"invalid in-addr.arpa or ip6.arpa name in DNS response");
ngx_resolver_free(r, name.data);
return;
valid:
if (rn == NULL || rn->query == NULL) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected DNS response for %V", &name);
ngx_resolver_free(r, name.data);
goto failed;
}
qident = (rn->query[0] << 8) + rn->query[1];
if (ident != qident) {
ngx_log_error(r->log_level, r->log, 0,
"wrong ident %ui in DNS response for %V, expect %ui",
ident, &name, qident);
ngx_resolver_free(r, name.data);
goto failed;
}
ngx_resolver_free(r, name.data);
if (code == 0 && nan == 0) {
code = NGX_RESOLVE_NXDOMAIN;
}
if (code) {
next = rn->waiting;
rn->waiting = NULL;
ngx_queue_remove(&rn->queue);
ngx_rbtree_delete(tree, &rn->node);
/* unlock addr mutex */
while (next) {
ctx = next;
ctx->state = code;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
next = ctx->next;
ctx->handler(ctx);
}
ngx_resolver_free_node(r, rn);
return;
}
i += sizeof(ngx_resolver_qs_t);
for (a = 0; a < nan; a++) {
start = i;
while (i < n) {
if (buf[i] & 0xc0) {
i += 2;
goto found;
}
if (buf[i] == 0) {
i++;
goto test_length;
}
i += 1 + buf[i];
}
goto short_response;
test_length:
if (i - start < 2) {
err = "invalid name in DNS response";
goto invalid;
}
found:
if (i + sizeof(ngx_resolver_an_t) >= n) {
goto short_response;
}
an = (ngx_resolver_an_t *) &buf[i];
type = (an->type_hi << 8) + an->type_lo;
class = (an->class_hi << 8) + an->class_lo;
len = (an->len_hi << 8) + an->len_lo;
ttl = (an->ttl[0] << 24) + (an->ttl[1] << 16)
+ (an->ttl[2] << 8) + (an->ttl[3]);
if (class != 1) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR class %ui in DNS response", class);
goto failed;
}
if (ttl < 0) {
ttl = 0;
}
ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver qt:%ui cl:%ui len:%uz",
type, class, len);
i += sizeof(ngx_resolver_an_t);
switch (type) {
case NGX_RESOLVE_PTR:
goto ptr;
case NGX_RESOLVE_CNAME:
break;
default:
ngx_log_error(r->log_level, r->log, 0,
"unexpected RR type %ui in DNS response", type);
}
i += len;
}
/* unlock addr mutex */
ngx_log_error(r->log_level, r->log, 0,
"no PTR type in DNS response");
return;
ptr:
if (ngx_resolver_copy(r, &name, buf, buf + i, buf + n) != NGX_OK) {
goto failed;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver an:%V", &name);
if (name.len != (size_t) rn->nlen
|| ngx_strncmp(name.data, rn->name, name.len) != 0)
{
if (rn->nlen) {
ngx_resolver_free(r, rn->name);
}
rn->nlen = (u_short) name.len;
rn->name = name.data;
name.data = ngx_resolver_dup(r, rn->name, name.len);
if (name.data == NULL) {
goto failed;
}
}
ngx_queue_remove(&rn->queue);
rn->valid = ngx_time() + (r->valid ? r->valid : ttl);
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(expire_queue, &rn->queue);
next = rn->waiting;
rn->waiting = NULL;
/* unlock addr mutex */
while (next) {
ctx = next;
ctx->state = NGX_OK;
ctx->valid = rn->valid;
ctx->name = name;
next = ctx->next;
ctx->handler(ctx);
}
ngx_resolver_free(r, name.data);
return;
short_response:
err = "short DNS response";
invalid:
/* unlock addr mutex */
ngx_log_error(r->log_level, r->log, 0, err);
return;
failed:
/* unlock addr mutex */
return;
}
static ngx_resolver_node_t *
ngx_resolver_lookup_name(ngx_resolver_t *r, ngx_str_t *name, uint32_t hash)
{
ngx_int_t rc;
ngx_rbtree_node_t *node, *sentinel;
ngx_resolver_node_t *rn;
node = r->name_rbtree.root;
sentinel = r->name_rbtree.sentinel;
while (node != sentinel) {
if (hash < node->key) {
node = node->left;
continue;
}
if (hash > node->key) {
node = node->right;
continue;
}
/* hash == node->key */
rn = ngx_resolver_node(node);
rc = ngx_memn2cmp(name->data, rn->name, name->len, rn->nlen);
if (rc == 0) {
return rn;
}
node = (rc < 0) ? node->left : node->right;
}
/* not found */
return NULL;
}
static ngx_resolver_node_t *
ngx_resolver_lookup_srv(ngx_resolver_t *r, ngx_str_t *name, uint32_t hash)
{
ngx_int_t rc;
ngx_rbtree_node_t *node, *sentinel;
ngx_resolver_node_t *rn;
node = r->srv_rbtree.root;
sentinel = r->srv_rbtree.sentinel;
while (node != sentinel) {
if (hash < node->key) {
node = node->left;
continue;
}
if (hash > node->key) {
node = node->right;
continue;
}
/* hash == node->key */
rn = ngx_resolver_node(node);
rc = ngx_memn2cmp(name->data, rn->name, name->len, rn->nlen);
if (rc == 0) {
return rn;
}
node = (rc < 0) ? node->left : node->right;
}
/* not found */
return NULL;
}
static ngx_resolver_node_t *
ngx_resolver_lookup_addr(ngx_resolver_t *r, in_addr_t addr)
{
ngx_rbtree_node_t *node, *sentinel;
node = r->addr_rbtree.root;
sentinel = r->addr_rbtree.sentinel;
while (node != sentinel) {
if (addr < node->key) {
node = node->left;
continue;
}
if (addr > node->key) {
node = node->right;
continue;
}
/* addr == node->key */
return ngx_resolver_node(node);
}
/* not found */
return NULL;
}
#if (NGX_HAVE_INET6)
static ngx_resolver_node_t *
ngx_resolver_lookup_addr6(ngx_resolver_t *r, struct in6_addr *addr,
uint32_t hash)
{
ngx_int_t rc;
ngx_rbtree_node_t *node, *sentinel;
ngx_resolver_node_t *rn;
node = r->addr6_rbtree.root;
sentinel = r->addr6_rbtree.sentinel;
while (node != sentinel) {
if (hash < node->key) {
node = node->left;
continue;
}
if (hash > node->key) {
node = node->right;
continue;
}
/* hash == node->key */
rn = ngx_resolver_node(node);
rc = ngx_memcmp(addr, &rn->addr6, 16);
if (rc == 0) {
return rn;
}
node = (rc < 0) ? node->left : node->right;
}
/* not found */
return NULL;
}
#endif
static void
ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
{
ngx_rbtree_node_t **p;
ngx_resolver_node_t *rn, *rn_temp;
for ( ;; ) {
if (node->key < temp->key) {
p = &temp->left;
} else if (node->key > temp->key) {
p = &temp->right;
} else { /* node->key == temp->key */
rn = ngx_resolver_node(node);
rn_temp = ngx_resolver_node(temp);
p = (ngx_memn2cmp(rn->name, rn_temp->name, rn->nlen, rn_temp->nlen)
< 0) ? &temp->left : &temp->right;
}
if (*p == sentinel) {
break;
}
temp = *p;
}
*p = node;
node->parent = temp;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_red(node);
}
#if (NGX_HAVE_INET6)
static void
ngx_resolver_rbtree_insert_addr6_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
{
ngx_rbtree_node_t **p;
ngx_resolver_node_t *rn, *rn_temp;
for ( ;; ) {
if (node->key < temp->key) {
p = &temp->left;
} else if (node->key > temp->key) {
p = &temp->right;
} else { /* node->key == temp->key */
rn = ngx_resolver_node(node);
rn_temp = ngx_resolver_node(temp);
p = (ngx_memcmp(&rn->addr6, &rn_temp->addr6, 16)
< 0) ? &temp->left : &temp->right;
}
if (*p == sentinel) {
break;
}
temp = *p;
}
*p = node;
node->parent = temp;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_red(node);
}
#endif
static ngx_int_t
ngx_resolver_create_name_query(ngx_resolver_t *r, ngx_resolver_node_t *rn,
ngx_str_t *name)
{
u_char *p, *s;
size_t len, nlen;
ngx_uint_t ident;
ngx_resolver_qs_t *qs;
ngx_resolver_hdr_t *query;
nlen = name->len ? (1 + name->len + 1) : 1;
len = sizeof(ngx_resolver_hdr_t) + nlen + sizeof(ngx_resolver_qs_t);
#if (NGX_HAVE_INET6)
p = ngx_resolver_alloc(r, r->ipv6 ? len * 2 : len);
#else
p = ngx_resolver_alloc(r, len);
#endif
if (p == NULL) {
return NGX_ERROR;
}
rn->qlen = (u_short) len;
rn->query = p;
#if (NGX_HAVE_INET6)
if (r->ipv6) {
rn->query6 = p + len;
}
#endif
query = (ngx_resolver_hdr_t *) p;
ident = ngx_random();
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve: \"%V\" A %i", name, ident & 0xffff);
query->ident_hi = (u_char) ((ident >> 8) & 0xff);
query->ident_lo = (u_char) (ident & 0xff);
/* recursion query */
query->flags_hi = 1; query->flags_lo = 0;
/* one question */
query->nqs_hi = 0; query->nqs_lo = 1;
query->nan_hi = 0; query->nan_lo = 0;
query->nns_hi = 0; query->nns_lo = 0;
query->nar_hi = 0; query->nar_lo = 0;
p += sizeof(ngx_resolver_hdr_t) + nlen;
qs = (ngx_resolver_qs_t *) p;
/* query type */
qs->type_hi = 0; qs->type_lo = NGX_RESOLVE_A;
/* IN query class */
qs->class_hi = 0; qs->class_lo = 1;
/* convert "www.example.com" to "\3www\7example\3com\0" */
len = 0;
p--;
*p-- = '\0';
if (name->len == 0) {
return NGX_DECLINED;
}
for (s = name->data + name->len - 1; s >= name->data; s--) {
if (*s != '.') {
*p = *s;
len++;
} else {
if (len == 0 || len > 255) {
return NGX_DECLINED;
}
*p = (u_char) len;
len = 0;
}
p--;
}
if (len == 0 || len > 255) {
return NGX_DECLINED;
}
*p = (u_char) len;
#if (NGX_HAVE_INET6)
if (!r->ipv6) {
return NGX_OK;
}
p = rn->query6;
ngx_memcpy(p, rn->query, rn->qlen);
query = (ngx_resolver_hdr_t *) p;
ident = ngx_random();
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve: \"%V\" AAAA %i", name, ident & 0xffff);
query->ident_hi = (u_char) ((ident >> 8) & 0xff);
query->ident_lo = (u_char) (ident & 0xff);
p += sizeof(ngx_resolver_hdr_t) + nlen;
qs = (ngx_resolver_qs_t *) p;
qs->type_lo = NGX_RESOLVE_AAAA;
#endif
return NGX_OK;
}
static ngx_int_t
ngx_resolver_create_srv_query(ngx_resolver_t *r, ngx_resolver_node_t *rn,
ngx_str_t *name)
{
u_char *p, *s;
size_t len, nlen;
ngx_uint_t ident;
ngx_resolver_qs_t *qs;
ngx_resolver_hdr_t *query;
nlen = name->len ? (1 + name->len + 1) : 1;
len = sizeof(ngx_resolver_hdr_t) + nlen + sizeof(ngx_resolver_qs_t);
p = ngx_resolver_alloc(r, len);
if (p == NULL) {
return NGX_ERROR;
}
rn->qlen = (u_short) len;
rn->query = p;
query = (ngx_resolver_hdr_t *) p;
ident = ngx_random();
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve: \"%V\" SRV %i", name, ident & 0xffff);
query->ident_hi = (u_char) ((ident >> 8) & 0xff);
query->ident_lo = (u_char) (ident & 0xff);
/* recursion query */
query->flags_hi = 1; query->flags_lo = 0;
/* one question */
query->nqs_hi = 0; query->nqs_lo = 1;
query->nan_hi = 0; query->nan_lo = 0;
query->nns_hi = 0; query->nns_lo = 0;
query->nar_hi = 0; query->nar_lo = 0;
p += sizeof(ngx_resolver_hdr_t) + nlen;
qs = (ngx_resolver_qs_t *) p;
/* query type */
qs->type_hi = 0; qs->type_lo = NGX_RESOLVE_SRV;
/* IN query class */
qs->class_hi = 0; qs->class_lo = 1;
/* converts "www.example.com" to "\3www\7example\3com\0" */
len = 0;
p--;
*p-- = '\0';
if (name->len == 0) {
return NGX_DECLINED;
}
for (s = name->data + name->len - 1; s >= name->data; s--) {
if (*s != '.') {
*p = *s;
len++;
} else {
if (len == 0 || len > 255) {
return NGX_DECLINED;
}
*p = (u_char) len;
len = 0;
}
p--;
}
if (len == 0 || len > 255) {
return NGX_DECLINED;
}
*p = (u_char) len;
return NGX_OK;
}
static ngx_int_t
ngx_resolver_create_addr_query(ngx_resolver_t *r, ngx_resolver_node_t *rn,
ngx_resolver_addr_t *addr)
{
u_char *p, *d;
size_t len;
in_addr_t inaddr;
ngx_int_t n;
ngx_uint_t ident;
ngx_resolver_hdr_t *query;
struct sockaddr_in *sin;
#if (NGX_HAVE_INET6)
struct sockaddr_in6 *sin6;
#endif
switch (addr->sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
len = sizeof(ngx_resolver_hdr_t)
+ 64 + sizeof(".ip6.arpa.") - 1
+ sizeof(ngx_resolver_qs_t);
break;
#endif
default: /* AF_INET */
len = sizeof(ngx_resolver_hdr_t)
+ sizeof(".255.255.255.255.in-addr.arpa.") - 1
+ sizeof(ngx_resolver_qs_t);
}
p = ngx_resolver_alloc(r, len);
if (p == NULL) {
return NGX_ERROR;
}
rn->query = p;
query = (ngx_resolver_hdr_t *) p;
ident = ngx_random();
query->ident_hi = (u_char) ((ident >> 8) & 0xff);
query->ident_lo = (u_char) (ident & 0xff);
/* recursion query */
query->flags_hi = 1; query->flags_lo = 0;
/* one question */
query->nqs_hi = 0; query->nqs_lo = 1;
query->nan_hi = 0; query->nan_lo = 0;
query->nns_hi = 0; query->nns_lo = 0;
query->nar_hi = 0; query->nar_lo = 0;
p += sizeof(ngx_resolver_hdr_t);
switch (addr->sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
sin6 = (struct sockaddr_in6 *) addr->sockaddr;
for (n = 15; n >= 0; n--) {
p = ngx_sprintf(p, "\1%xd\1%xd",
sin6->sin6_addr.s6_addr[n] & 0xf,
(sin6->sin6_addr.s6_addr[n] >> 4) & 0xf);
}
p = ngx_cpymem(p, "\3ip6\4arpa\0", 10);
break;
#endif
default: /* AF_INET */
sin = (struct sockaddr_in *) addr->sockaddr;
inaddr = ntohl(sin->sin_addr.s_addr);
for (n = 0; n < 32; n += 8) {
d = ngx_sprintf(&p[1], "%ud", (inaddr >> n) & 0xff);
*p = (u_char) (d - &p[1]);
p = d;
}
p = ngx_cpymem(p, "\7in-addr\4arpa\0", 14);
}
/* query type "PTR", IN query class */
p = ngx_cpymem(p, "\0\14\0\1", 4);
rn->qlen = (u_short) (p - rn->query);
return NGX_OK;
}
static ngx_int_t
ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name, u_char *buf, u_char *src,
u_char *last)
{
char *err;
u_char *p, *dst;
size_t len;
ngx_uint_t i, n;
p = src;
len = 0;
/*
* compression pointers allow to create endless loop, so we set limit;
* 128 pointers should be enough to store 255-byte name
*/
for (i = 0; i < 128; i++) {
n = *p++;
if (n == 0) {
goto done;
}
if (n & 0xc0) {
if ((n & 0xc0) != 0xc0) {
err = "invalid label type in DNS response";
goto invalid;
}
if (p >= last) {
err = "name is out of DNS response";
goto invalid;
}
n = ((n & 0x3f) << 8) + *p;
p = &buf[n];
} else {
len += 1 + n;
p = &p[n];
}
if (p >= last) {
err = "name is out of DNS response";
goto invalid;
}
}
err = "compression pointers loop in DNS response";
invalid:
ngx_log_error(r->log_level, r->log, 0, err);
return NGX_ERROR;
done:
if (name == NULL) {
return NGX_OK;
}
if (len == 0) {
ngx_str_null(name);
return NGX_OK;
}
dst = ngx_resolver_alloc(r, len);
if (dst == NULL) {
return NGX_ERROR;
}
name->data = dst;
for ( ;; ) {
n = *src++;
if (n == 0) {
name->len = dst - name->data - 1;
return NGX_OK;
}
if (n & 0xc0) {
n = ((n & 0x3f) << 8) + *src;
src = &buf[n];
} else {
ngx_strlow(dst, src, n);
dst += n;
src += n;
*dst++ = '.';
}
}
}
static ngx_int_t
ngx_resolver_set_timeout(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx)
{
if (ctx->event || ctx->timeout == 0) {
return NGX_OK;
}
ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
if (ctx->event == NULL) {
return NGX_ERROR;
}
ctx->event->handler = ngx_resolver_timeout_handler;
ctx->event->data = ctx;
ctx->event->log = r->log;
ctx->event->cancelable = ctx->cancelable;
ctx->ident = -1;
ngx_add_timer(ctx->event, ctx->timeout);
return NGX_OK;
}
static void
ngx_resolver_timeout_handler(ngx_event_t *ev)
{
ngx_resolver_ctx_t *ctx;
ctx = ev->data;
ctx->state = NGX_RESOLVE_TIMEDOUT;
ctx->handler(ctx);
}
static void
ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn)
{
ngx_uint_t i;
/* lock alloc mutex */
if (rn->query) {
ngx_resolver_free_locked(r, rn->query);
}
if (rn->name) {
ngx_resolver_free_locked(r, rn->name);
}
if (rn->cnlen) {
ngx_resolver_free_locked(r, rn->u.cname);
}
if (rn->naddrs > 1 && rn->naddrs != (u_short) -1) {
ngx_resolver_free_locked(r, rn->u.addrs);
}
#if (NGX_HAVE_INET6)
if (rn->naddrs6 > 1 && rn->naddrs6 != (u_short) -1) {
ngx_resolver_free_locked(r, rn->u6.addrs6);
}
#endif
if (rn->nsrvs) {
for (i = 0; i < (ngx_uint_t) rn->nsrvs; i++) {
if (rn->u.srvs[i].name.data) {
ngx_resolver_free_locked(r, rn->u.srvs[i].name.data);
}
}
ngx_resolver_free_locked(r, rn->u.srvs);
}
ngx_resolver_free_locked(r, rn);
/* unlock alloc mutex */
}
static void *
ngx_resolver_alloc(ngx_resolver_t *r, size_t size)
{
u_char *p;
/* lock alloc mutex */
p = ngx_alloc(size, r->log);
/* unlock alloc mutex */
return p;
}
static void *
ngx_resolver_calloc(ngx_resolver_t *r, size_t size)
{
u_char *p;
p = ngx_resolver_alloc(r, size);
if (p) {
ngx_memzero(p, size);
}
return p;
}
static void
ngx_resolver_free(ngx_resolver_t *r, void *p)
{
/* lock alloc mutex */
ngx_free(p);
/* unlock alloc mutex */
}
static void
ngx_resolver_free_locked(ngx_resolver_t *r, void *p)
{
ngx_free(p);
}
static void *
ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size)
{
void *dst;
dst = ngx_resolver_alloc(r, size);
if (dst == NULL) {
return dst;
}
ngx_memcpy(dst, src, size);
return dst;
}
static ngx_resolver_addr_t *
ngx_resolver_export(ngx_resolver_t *r, ngx_resolver_node_t *rn,
ngx_uint_t rotate)
{
ngx_uint_t d, i, j, n;
in_addr_t *addr;
ngx_sockaddr_t *sockaddr;
struct sockaddr_in *sin;
ngx_resolver_addr_t *dst;
#if (NGX_HAVE_INET6)
struct in6_addr *addr6;
struct sockaddr_in6 *sin6;
#endif
n = rn->naddrs;
#if (NGX_HAVE_INET6)
n += rn->naddrs6;
#endif
dst = ngx_resolver_calloc(r, n * sizeof(ngx_resolver_addr_t));
if (dst == NULL) {
return NULL;
}
sockaddr = ngx_resolver_calloc(r, n * sizeof(ngx_sockaddr_t));
if (sockaddr == NULL) {
ngx_resolver_free(r, dst);
return NULL;
}
i = 0;
d = rotate ? ngx_random() % n : 0;
if (rn->naddrs) {
j = rotate ? ngx_random() % rn->naddrs : 0;
addr = (rn->naddrs == 1) ? &rn->u.addr : rn->u.addrs;
do {
sin = &sockaddr[d].sockaddr_in;
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = addr[j++];
dst[d].sockaddr = (struct sockaddr *) sin;
dst[d++].socklen = sizeof(struct sockaddr_in);
if (d == n) {
d = 0;
}
if (j == (ngx_uint_t) rn->naddrs) {
j = 0;
}
} while (++i < (ngx_uint_t) rn->naddrs);
}
#if (NGX_HAVE_INET6)
if (rn->naddrs6) {
j = rotate ? ngx_random() % rn->naddrs6 : 0;
addr6 = (rn->naddrs6 == 1) ? &rn->u6.addr6 : rn->u6.addrs6;
do {
sin6 = &sockaddr[d].sockaddr_in6;
sin6->sin6_family = AF_INET6;
ngx_memcpy(sin6->sin6_addr.s6_addr, addr6[j++].s6_addr, 16);
dst[d].sockaddr = (struct sockaddr *) sin6;
dst[d++].socklen = sizeof(struct sockaddr_in6);
if (d == n) {
d = 0;
}
if (j == rn->naddrs6) {
j = 0;
}
} while (++i < n);
}
#endif
return dst;
}
static void
ngx_resolver_report_srv(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx)
{
ngx_uint_t naddrs, nsrvs, nw, i, j, k, l, m, n, w;
ngx_resolver_addr_t *addrs;
ngx_resolver_srv_name_t *srvs;
srvs = ctx->srvs;
nsrvs = ctx->nsrvs;
naddrs = 0;
for (i = 0; i < nsrvs; i++) {
if (srvs[i].state == NGX_ERROR) {
ctx->state = NGX_ERROR;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
ctx->handler(ctx);
return;
}
naddrs += srvs[i].naddrs;
}
if (naddrs == 0) {
ctx->state = srvs[0].state;
for (i = 0; i < nsrvs; i++) {
if (srvs[i].state == NGX_RESOLVE_NXDOMAIN) {
ctx->state = NGX_RESOLVE_NXDOMAIN;
break;
}
}
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
ctx->handler(ctx);
return;
}
addrs = ngx_resolver_calloc(r, naddrs * sizeof(ngx_resolver_addr_t));
if (addrs == NULL) {
ctx->state = NGX_ERROR;
ctx->valid = ngx_time() + (r->valid ? r->valid : 10);
ctx->handler(ctx);
return;
}
i = 0;
n = 0;
do {
nw = 0;
for (j = i; j < nsrvs; j++) {
if (srvs[j].priority != srvs[i].priority) {
break;
}
nw += srvs[j].naddrs * srvs[j].weight;
}
if (nw == 0) {
goto next_srv;
}
w = ngx_random() % nw;
for (k = i; k < j; k++) {
if (w < srvs[k].naddrs * srvs[k].weight) {
break;
}
w -= srvs[k].naddrs * srvs[k].weight;
}
for (l = i; l < j; l++) {
for (m = 0; m < srvs[k].naddrs; m++) {
addrs[n].socklen = srvs[k].addrs[m].socklen;
addrs[n].sockaddr = srvs[k].addrs[m].sockaddr;
addrs[n].name = srvs[k].name;
addrs[n].priority = srvs[k].priority;
addrs[n].weight = srvs[k].weight;
n++;
}
if (++k == j) {
k = i;
}
}
next_srv:
i = j;
} while (i < ctx->nsrvs);
ctx->state = NGX_OK;
ctx->addrs = addrs;
ctx->naddrs = naddrs;
ctx->handler(ctx);
ngx_resolver_free(r, addrs);
}
char *
ngx_resolver_strerror(ngx_int_t err)
{
static char *errors[] = {
"Format error", /* FORMERR */
"Server failure", /* SERVFAIL */
"Host not found", /* NXDOMAIN */
"Unimplemented", /* NOTIMP */
"Operation refused" /* REFUSED */
};
if (err > 0 && err < 6) {
return errors[err - 1];
}
if (err == NGX_RESOLVE_TIMEDOUT) {
return "Operation timed out";
}
return "Unknown error";
}
static u_char *
ngx_resolver_log_error(ngx_log_t *log, u_char *buf, size_t len)
{
u_char *p;
ngx_resolver_connection_t *rec;
p = buf;
if (log->action) {
p = ngx_snprintf(buf, len, " while %s", log->action);
len -= p - buf;
}
rec = log->data;
if (rec) {
p = ngx_snprintf(p, len, ", resolver: %V", &rec->server);
}
return p;
}
static ngx_int_t
ngx_udp_connect(ngx_resolver_connection_t *rec)
{
int rc;
ngx_int_t event;
ngx_event_t *rev, *wev;
ngx_socket_t s;
ngx_connection_t *c;
s = ngx_socket(rec->sockaddr->sa_family, SOCK_DGRAM, 0);
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, &rec->log, 0, "UDP socket %d", s);
if (s == (ngx_socket_t) -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_socket_n " failed");
return NGX_ERROR;
}
c = ngx_get_connection(s, &rec->log);
if (c == NULL) {
if (ngx_close_socket(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_close_socket_n " failed");
}
return NGX_ERROR;
}
if (ngx_nonblocking(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_nonblocking_n " failed");
goto failed;
}
rev = c->read;
wev = c->write;
rev->log = &rec->log;
wev->log = &rec->log;
rec->udp = c;
c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
c->start_time = ngx_current_msec;
ngx_log_debug3(NGX_LOG_DEBUG_EVENT, &rec->log, 0,
"connect to %V, fd:%d #%uA", &rec->server, s, c->number);
rc = connect(s, rec->sockaddr, rec->socklen);
/* TODO: iocp */
if (rc == -1) {
ngx_log_error(NGX_LOG_CRIT, &rec->log, ngx_socket_errno,
"connect() failed");
goto failed;
}
/* UDP sockets are always ready to write */
wev->ready = 1;
event = (ngx_event_flags & NGX_USE_CLEAR_EVENT) ?
/* kqueue, epoll */ NGX_CLEAR_EVENT:
/* select, poll, /dev/poll */ NGX_LEVEL_EVENT;
/* eventport event type has no meaning: oneshot only */
if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) {
goto failed;
}
return NGX_OK;
failed:
ngx_close_connection(c);
rec->udp = NULL;
return NGX_ERROR;
}
static ngx_int_t
ngx_tcp_connect(ngx_resolver_connection_t *rec)
{
int rc;
ngx_int_t event;
ngx_err_t err;
ngx_uint_t level;
ngx_socket_t s;
ngx_event_t *rev, *wev;
ngx_connection_t *c;
s = ngx_socket(rec->sockaddr->sa_family, SOCK_STREAM, 0);
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, &rec->log, 0, "TCP socket %d", s);
if (s == (ngx_socket_t) -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_socket_n " failed");
return NGX_ERROR;
}
c = ngx_get_connection(s, &rec->log);
if (c == NULL) {
if (ngx_close_socket(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_close_socket_n " failed");
}
return NGX_ERROR;
}
if (ngx_nonblocking(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_nonblocking_n " failed");
goto failed;
}
rev = c->read;
wev = c->write;
rev->log = &rec->log;
wev->log = &rec->log;
rec->tcp = c;
c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
c->start_time = ngx_current_msec;
if (ngx_add_conn) {
if (ngx_add_conn(c) == NGX_ERROR) {
goto failed;
}
}
ngx_log_debug3(NGX_LOG_DEBUG_EVENT, &rec->log, 0,
"connect to %V, fd:%d #%uA", &rec->server, s, c->number);
rc = connect(s, rec->sockaddr, rec->socklen);
if (rc == -1) {
err = ngx_socket_errno;
if (err != NGX_EINPROGRESS
#if (NGX_WIN32)
/* Winsock returns WSAEWOULDBLOCK (NGX_EAGAIN) */
&& err != NGX_EAGAIN
#endif
)
{
if (err == NGX_ECONNREFUSED
#if (NGX_LINUX)
/*
* Linux returns EAGAIN instead of ECONNREFUSED
* for unix sockets if listen queue is full
*/
|| err == NGX_EAGAIN
#endif
|| err == NGX_ECONNRESET
|| err == NGX_ENETDOWN
|| err == NGX_ENETUNREACH
|| err == NGX_EHOSTDOWN
|| err == NGX_EHOSTUNREACH)
{
level = NGX_LOG_ERR;
} else {
level = NGX_LOG_CRIT;
}
ngx_log_error(level, &rec->log, err, "connect() to %V failed",
&rec->server);
ngx_close_connection(c);
rec->tcp = NULL;
return NGX_ERROR;
}
}
if (ngx_add_conn) {
if (rc == -1) {
/* NGX_EINPROGRESS */
return NGX_AGAIN;
}
ngx_log_debug0(NGX_LOG_DEBUG_EVENT, &rec->log, 0, "connected");
wev->ready = 1;
return NGX_OK;
}
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, &rec->log, ngx_socket_errno,
"connect(): %d", rc);
if (ngx_blocking(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, &rec->log, ngx_socket_errno,
ngx_blocking_n " failed");
goto failed;
}
/*
* FreeBSD's aio allows to post an operation on non-connected socket.
* NT does not support it.
*
* TODO: check in Win32, etc. As workaround we can use NGX_ONESHOT_EVENT
*/
rev->ready = 1;
wev->ready = 1;
return NGX_OK;
}
if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {
/* kqueue */
event = NGX_CLEAR_EVENT;
} else {
/* select, poll, /dev/poll */
event = NGX_LEVEL_EVENT;
}
if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) {
goto failed;
}
if (rc == -1) {
/* NGX_EINPROGRESS */
if (ngx_add_event(wev, NGX_WRITE_EVENT, event) != NGX_OK) {
goto failed;
}
return NGX_AGAIN;
}
ngx_log_debug0(NGX_LOG_DEBUG_EVENT, &rec->log, 0, "connected");
wev->ready = 1;
return NGX_OK;
failed:
ngx_close_connection(c);
rec->tcp = NULL;
return NGX_ERROR;
}
static ngx_int_t
ngx_resolver_cmp_srvs(const void *one, const void *two)
{
ngx_int_t p1, p2;
ngx_resolver_srv_t *first, *second;
first = (ngx_resolver_srv_t *) one;
second = (ngx_resolver_srv_t *) two;
p1 = first->priority;
p2 = second->priority;
return p1 - p2;
}
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