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nginx/src/core/ngx_resolver.c
Igor Sysoev cb4d53861c resolver
2007-11-23 17:13:26 +00:00

2011 lines
43 KiB
C
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/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#define NGX_RESOLVER_UDP_SIZE 4096
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_query_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;
ngx_int_t ngx_udp_connect(ngx_udp_connection_t *uc);
static ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r,
ngx_resolver_ctx_t *ctx);
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_create_name_query(ngx_resolver_node_t *rn,
ngx_resolver_ctx_t *ctx);
static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_node_t *rn,
ngx_resolver_ctx_t *ctx);
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 void ngx_resolver_read_response(ngx_event_t *rev);
static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf,
size_t n);
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 nan, ngx_uint_t i);
static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code);
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_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 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_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);
/* STUB: ngx_peer_addr_t * */
ngx_resolver_t *
ngx_resolver_create(ngx_peer_addr_t *addr, ngx_log_t *log)
{
ngx_resolver_t *r;
ngx_udp_connection_t *uc;
r = ngx_calloc(sizeof(ngx_resolver_t), log);
if (r == NULL) {
return NULL;
}
uc = ngx_calloc(sizeof(ngx_udp_connection_t), log);
if (uc == NULL) {
return NULL;
}
r->event = ngx_calloc(sizeof(ngx_event_t), log);
if (r->event == NULL) {
return NULL;
}
ngx_rbtree_sentinel_init(&r->name_sentinel);
r->name_rbtree.root = &r->name_sentinel;
r->name_rbtree.sentinel = &r->name_sentinel;
r->name_rbtree.insert = ngx_resolver_rbtree_insert_value;
ngx_rbtree_sentinel_init(&r->addr_sentinel);
r->addr_rbtree.root = &r->addr_sentinel;
r->addr_rbtree.sentinel = &r->addr_sentinel;
r->addr_rbtree.insert = ngx_rbtree_insert_value;
r->name_resend_queue.prev = &r->name_resend_queue;
r->name_resend_queue.next = &r->name_resend_queue;
r->addr_resend_queue.prev = &r->addr_resend_queue;
r->addr_resend_queue.next = &r->addr_resend_queue;
r->name_expire_queue.prev = &r->name_expire_queue;
r->name_expire_queue.next = &r->name_expire_queue;
r->addr_expire_queue.prev = &r->addr_expire_queue;
r->addr_expire_queue.next = &r->addr_expire_queue;
r->event->handler = ngx_resolver_resend_handler;
r->event->data = r;
r->event->log = log;
r->ident = -1;
r->udp_connection = uc;
r->resend_timeout = 5;
r->expire = 30;
r->valid = 300;
r->log = log;
r->log_level = NGX_LOG_ALERT;
uc->sockaddr = addr->sockaddr;
uc->socklen = addr->socklen;
uc->server = addr->name;
uc->log = log;
return r;
}
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 = addr;
temp->quick = 1;
return temp;
}
}
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)
{
ngx_int_t rc;
ngx_resolver_t *r;
r = ctx->resolver;
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolve: \"%V\"", &ctx->name);
if (ctx->quick) {
ctx->handler(ctx);
return NGX_OK;
}
/* lock name mutex */
rc = ngx_resolve_name_locked(r, ctx);
if (rc == NGX_OK) {
return NGX_OK;
}
/* unlock name mutex */
if (rc == NGX_AGAIN) {
return NGX_OK;
}
/* lock alloc mutex */
if (ctx->event) {
ngx_resolver_free_locked(r, ctx->event);
}
ngx_resolver_free_locked(r, ctx);
/* unlock alloc mutex */
return NGX_ERROR;
}
void
ngx_resolve_name_done(ngx_resolver_ctx_t *ctx)
{
uint32_t hash;
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->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
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:
ngx_resolver_expire(r, &r->name_rbtree, &r->name_expire_queue);
/* unlock name mutex */
ngx_resolver_free(r, ctx);
}
/* NGX_RESOLVE_A only */
static ngx_int_t
ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx)
{
uint32_t hash;
in_addr_t addr, *addrs;
ngx_uint_t naddrs;
ngx_resolver_ctx_t *next;
ngx_resolver_node_t *rn;
hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
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(&r->name_expire_queue, &rn->queue);
naddrs = rn->naddrs;
if (naddrs) {
/* NGX_RESOLVE_A answer */
if (naddrs != 1) {
addr = 0;
addrs = ngx_resolver_dup(r, rn->u.addrs,
naddrs * sizeof(in_addr_t));
if (addrs == NULL) {
return NGX_ERROR;
}
} else {
addr = rn->u.addr;
addrs = NULL;
}
ctx->next = rn->waiting;
rn->waiting = NULL;
/* unlock name mutex */
do {
ctx->state = NGX_OK;
ctx->naddrs = naddrs;
ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
ctx->addr = addr;
next = ctx->next;
ctx->handler(ctx);
ctx = next;
} while (ctx);
if (addrs) {
ngx_resolver_free(r, addrs);
}
return NGX_OK;
}
/* NGX_RESOLVE_CNAME */
ctx->name.len = rn->cnlen;
ctx->name.data = rn->u.cname;
return ngx_resolve_name_locked(r, ctx);
}
if (rn->waiting) {
ctx->next = rn->waiting;
rn->waiting = ctx;
return NGX_AGAIN;
}
ngx_queue_remove(&rn->queue);
/* lock alloc mutex */
ngx_resolver_free_locked(r, rn->query);
if (rn->cnlen) {
ngx_resolver_free_locked(r, rn->u.cname);
}
if (rn->naddrs > 1) {
ngx_resolver_free_locked(r, rn->u.addrs);
}
/* 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, ctx->name.data, ctx->name.len);
if (rn->name == NULL) {
ngx_resolver_free(r, rn);
return NGX_ERROR;
}
rn->node.key = hash;
rn->nlen = (u_short) ctx->name.len;
ngx_rbtree_insert(&r->name_rbtree, &rn->node);
}
if (ngx_resolver_create_name_query(rn, ctx) != NGX_OK) {
goto failed;
}
if (ngx_resolver_send_query(r, rn) != NGX_OK) {
goto failed;
}
if (ctx->event == NULL) {
ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
if (ctx->event == NULL) {
goto failed;
}
ctx->event->handler = ngx_resolver_timeout_handler;
ctx->event->data = ctx;
ctx->event->log = r->log;
ctx->ident = -1;
ngx_add_timer(ctx->event, ctx->timeout);
}
if (ngx_queue_empty(&r->name_resend_queue)) {
ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
}
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(&r->name_resend_queue, &rn->queue);
rn->cnlen = 0;
rn->naddrs = 0;
rn->valid = 0;
rn->waiting = ctx;
ctx->state = NGX_AGAIN;
return NGX_AGAIN;
failed:
ngx_rbtree_delete(&r->name_rbtree, &rn->node);
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)
{
ngx_resolver_t *r;
ngx_resolver_node_t *rn;
r = ctx->resolver;
ctx->addr = ntohl(ctx->addr);
/* lock addr mutex */
rn = ngx_resolver_lookup_addr(r, ctx->addr);
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(&r->addr_expire_queue, &rn->queue);
ctx->name.len = rn->nlen;
ctx->name.data = ngx_resolver_dup(r, rn->name, rn->nlen);
if (ctx->name.data == NULL) {
goto failed;
}
/* unlock addr mutex */
ctx->state = NGX_OK;
ctx->handler(ctx);
ngx_resolver_free(r, ctx->name.data);
return NGX_OK;
}
if (rn->waiting) {
ctx->next = rn->waiting;
rn->waiting = ctx;
return NGX_AGAIN;
}
ngx_queue_remove(&rn->queue);
ngx_resolver_free(r, rn->query);
} else {
rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
if (rn == NULL) {
goto failed;
}
rn->node.key = ctx->addr;
ngx_rbtree_insert(&r->addr_rbtree, &rn->node);
}
if (ngx_resolver_create_addr_query(rn, ctx) != NGX_OK) {
goto failed;
}
if (ngx_resolver_send_query(r, rn) != NGX_OK) {
goto failed;
}
ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
if (ctx->event == NULL) {
goto failed;
}
ctx->event->handler = ngx_resolver_timeout_handler;
ctx->event->data = ctx;
ctx->event->log = r->log;
ctx->ident = -1;
ngx_add_timer(ctx->event, ctx->timeout);
if (ngx_queue_empty(&r->addr_resend_queue)) {
ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
}
rn->expire = ngx_time() + r->resend_timeout;
ngx_queue_insert_head(&r->addr_resend_queue, &rn->queue);
rn->cnlen = 0;
rn->naddrs = 0;
rn->name = NULL;
rn->nlen = 0;
rn->valid = 0;
rn->waiting = ctx;
/* unlock addr mutex */
ctx->state = NGX_AGAIN;
return NGX_OK;
failed:
if (rn) {
ngx_rbtree_delete(&r->addr_rbtree, &rn->node);
ngx_resolver_free(r, rn);
}
/* 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 */
return NGX_ERROR;
}
void
ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx)
{
in_addr_t addr;
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 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 = ngx_resolver_lookup_addr(r, ctx->addr);
if (rn) {
p = &rn->waiting;
w = rn->waiting;
while (w) {
if (w == ctx) {
*p = w->next;
goto done;
}
p = &w->next;
w = w->next;
}
}
addr = ntohl(ctx->addr);
ngx_log_error(NGX_LOG_ALERT, r->log, 0,
"could not cancel %ud.%ud.%ud.%ud resolving",
(addr >> 24) & 0xff, (addr >> 16) & 0xff,
(addr >> 8) & 0xff, addr & 0xff);
}
done:
ngx_resolver_expire(r, &r->addr_rbtree, &r->addr_expire_queue);
/* unlock addr mutex */
ngx_resolver_free(r, ctx);
}
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;
}
#if (NGX_DEBUG)
{
ngx_str_t s;
s.len = rn->nlen;
s.data = rn->name;
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver expire \"%V\"", &s);
}
#endif
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)
{
ssize_t n;
ngx_udp_connection_t *uc;
uc = r->udp_connection;
if (uc->connection == NULL) {
if (ngx_udp_connect(uc) != NGX_OK) {
return NGX_ERROR;
}
uc->connection->data = r;
uc->connection->read->handler = ngx_resolver_read_response;
}
n = ngx_send(uc->connection, rn->query, rn->qlen);
if (n == -1) {
return NGX_ERROR;
}
if ((size_t) n != (size_t) rn->qlen) {
ngx_log_error(NGX_LOG_CRIT, uc->log, 0, "send() incomplete");
return NGX_ERROR;
}
return NGX_OK;
}
static void
ngx_resolver_resend_handler(ngx_event_t *ev)
{
time_t timer, atimer, ntimer;
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);
/* unlock name mutex */
/* lock addr mutex */
atimer = ngx_resolver_resend(r, &r->addr_rbtree, &r->addr_resend_queue);
/* unlock addr mutex */
if (ntimer == 0) {
timer = atimer;
} else if (atimer == 0) {
timer = ntimer;
} else {
timer = (atimer < ntimer) ? atimer : ntimer;
}
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;
}
#if (NGX_DEBUG)
{
ngx_str_t s;
s.len = rn->nlen;
s.data = rn->name;
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver resend \"%V\" %p", &s, rn->waiting);
}
#endif
ngx_queue_remove(q);
if (rn->waiting) {
if (ngx_resolver_send_query(r, rn) == NGX_OK) {
rn->expire = now + r->resend_timeout;
ngx_queue_insert_head(queue, &rn->queue);
continue;
}
}
ngx_rbtree_delete(tree, &rn->node);
ngx_resolver_free_node(r, rn);
}
}
static void
ngx_resolver_read_response(ngx_event_t *rev)
{
ssize_t n;
ngx_connection_t *c;
u_char buf[NGX_RESOLVER_UDP_SIZE];
c = rev->data;
do {
n = ngx_recv(c, buf, NGX_RESOLVER_UDP_SIZE);
if (n == -1) {
return;
}
ngx_resolver_process_response(c->data, buf, n);
} while (rev->ready);
}
static void
ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
{
char *err;
size_t len;
ngx_uint_t i, ident, flags, code, nqs, nan, qtype, qclass;
ngx_resolver_qs_t *qs;
ngx_resolver_query_t *query;
if ((size_t) n < sizeof(ngx_resolver_query_t) + 1) {
goto short_response;
}
query = (ngx_resolver_query_t *) buf;
ident = (query->ident_hi << 8) + query->ident_lo;
flags = (query->flags_hi << 8) + query->flags_lo;
nqs = (query->nqs_hi << 8) + query->nqs_lo;
nan = (query->nan_hi << 8) + query->nan_lo;
ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver DNS response %d fl:%04Xud %d/%d/%d/%d",
ident, flags, nqs, nan,
(query->nns_hi << 8) + query->nns_lo,
(query->nar_hi << 8) + query->nar_lo);
if (!(flags & 0x8000)) {
ngx_log_error(r->log_level, r->log, 0,
"invalid DNS response %d fl:%04Xud", ident, flags);
return;
}
code = flags & 0x7f;
if (code == NGX_RESOLVE_FORMERR || code > NGX_RESOLVE_REFUSED) {
ngx_log_error(r->log_level, r->log, 0,
"DNS error (%d: %s), query id:%d",
code, ngx_resolver_strerror(code), ident);
return;
}
if (nqs != 1) {
err = "invalid number of questions in DNS response";
goto done;
}
if (code == 0 && nan == 0) {
err = "no answers in DNS response";
goto done;
}
i = sizeof(ngx_resolver_query_t);
while (i < (ngx_uint_t) n) {
if (buf[i] == '\0') {
goto found;
}
len = buf[i];
i += 1 + len;
}
goto short_response;
found:
if (i++ == 0) {
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:%d cl:%d", qtype, qclass);
if (qclass != 1) {
ngx_log_error(r->log_level, r->log, 0,
"unknown query class %d in DNS response", qclass);
return;
}
switch (qtype) {
case NGX_RESOLVE_A:
ngx_resolver_process_a(r, buf, n, ident, code, nan,
i + sizeof(ngx_resolver_qs_t));
break;
case NGX_RESOLVE_PTR:
ngx_resolver_process_ptr(r, buf, n, ident, code);
break;
default:
ngx_log_error(r->log_level, r->log, 0,
"unknown query type %d in DNS response", qtype);
return;
}
return;
short_response:
err = "short dns response";
done:
ngx_log_error(r->log_level, r->log, 0, err);
return;
}
static void
ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans)
{
char *err;
u_char *cname;
size_t len;
uint32_t hash;
in_addr_t addr, *addrs;
ngx_str_t name;
ngx_uint_t qtype, qident, naddrs, a, i, n, start;
ngx_resolver_an_t *an;
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_node_t *rn;
if (ngx_resolver_copy(r, &name, buf, &buf[12], &buf[last]) != 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 || rn->query == NULL) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected response for %V", &name);
goto failed;
}
qident = (rn->query[0] << 8) + rn->query[1];
if (ident != qident) {
ngx_log_error(r->log_level, r->log, 0,
"wrong ident %d response for %V, expect %d",
ident, &name, qident);
goto failed;
}
if (code) {
next = rn->waiting;
rn->waiting = NULL;
ngx_queue_remove(&rn->queue);
ngx_rbtree_delete(&r->name_rbtree, &rn->node);
ngx_resolver_free_node(r, rn);
/* unlock name mutex */
while (next) {
ctx = next;
ctx->state = code;
next = ctx->next;
ctx->handler(ctx);
}
return;
}
i = ans;
naddrs = 0;
addr = 0;
addrs = NULL;
cname = NULL;
qtype = 0;
for (a = 0; a < nan; a++) {
start = i;
while (i < last) {
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) >= last) {
goto short_response;
}
an = (ngx_resolver_an_t *) &buf[i];
qtype = (an->type_hi << 8) + an->type_lo;
len = (an->len_hi << 8) + an->len_lo;
if (qtype == NGX_RESOLVE_A) {
i += sizeof(ngx_resolver_an_t);
if (i + len > last) {
goto short_response;
}
addr = htonl((buf[i] << 24) + (buf[i + 1] << 16)
+ (buf[i + 2] << 8) + (buf[i + 3]));
naddrs++;
i += len;
} else if (qtype == NGX_RESOLVE_CNAME) {
cname = &buf[i] + sizeof(ngx_resolver_an_t);
i += sizeof(ngx_resolver_an_t) + len;
}
}
ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver naddrs:%ui cname:%p", naddrs, cname);
if (naddrs) {
if (naddrs == 1) {
rn->u.addr = addr;
} else {
addrs = ngx_resolver_alloc(r, naddrs * sizeof(in_addr_t));
if (addrs == NULL) {
return;
}
n = 0;
i = ans;
for (a = 0; a < nan; a++) {
for ( ;; ) {
if (buf[i] & 0xc0) {
i += 2;
goto ok;
}
if (buf[i] == 0) {
i++;
goto ok;
}
i += 1 + buf[i];
}
ok:
an = (ngx_resolver_an_t *) &buf[i];
qtype = (an->type_hi << 8) + an->type_lo;
len = (an->len_hi << 8) + an->len_lo;
i += sizeof(ngx_resolver_an_t);
if (qtype == NGX_RESOLVE_A) {
addrs[n++] = htonl((buf[i] << 24) + (buf[i + 1] << 16)
+ (buf[i + 2] << 8) + (buf[i + 3]));
if (n == naddrs) {
break;
}
}
i += len;
}
rn->u.addrs = addrs;
addrs = ngx_resolver_dup(r, rn->u.addrs,
naddrs * sizeof(in_addr_t));
if (addrs == NULL) {
return;
}
}
rn->naddrs = (u_short) naddrs;
ngx_queue_remove(&rn->queue);
rn->valid = ngx_time() + r->valid;
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->naddrs = naddrs;
ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
ctx->addr = addr;
next = ctx->next;
ctx->handler(ctx);
}
if (naddrs) {
ngx_resolver_free(r, addrs);
}
return;
} else if (cname) {
/* CNAME only */
if (ngx_resolver_copy(r, &name, buf, cname, &buf[last]) != NGX_OK) {
return;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver cname:\"%V\"", &name);
rn->cnlen = (u_short) name.len;
rn->u.cname = name.data;
rn->valid = ngx_time() + r->valid;
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
ctx = rn->waiting;
rn->waiting = NULL;
if (ctx) {
ctx->name = name;
(void) ngx_resolve_name_locked(r, ctx);
}
return;
}
ngx_log_error(r->log_level, r->log, 0,
"no A or CNAME types in DNS responses, unknown query type: %d",
qtype);
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_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
ngx_uint_t ident, ngx_uint_t code)
{
char *err;
size_t len;
in_addr_t addr;
ngx_int_t digit;
ngx_str_t name;
ngx_uint_t i, mask, qtype, qclass, qident;
ngx_resolver_an_t *an;
ngx_resolver_ctx_t *ctx, *next;
ngx_resolver_node_t *rn;
if (ngx_resolver_copy(r, NULL, buf, &buf[12], &buf[n]) != NGX_OK) {
goto invalid_in_addr_arpa;
}
addr = 0;
i = 12;
for (mask = 0; mask < 32; mask += 8) {
len = buf[i++];
digit = ngx_atoi(&buf[i], len);
if (digit == NGX_ERROR || digit > 255) {
goto invalid_in_addr_arpa;
}
addr += digit << mask;
i += len;
}
if (ngx_strcmp(&buf[i], "\7in-addr\4arpa") != 0) {
goto invalid_in_addr_arpa;
}
/* lock addr mutex */
rn = ngx_resolver_lookup_addr(r, addr);
if (rn == NULL || rn->query == NULL) {
ngx_log_error(r->log_level, r->log, 0,
"unexpected response for %ud.%ud.%ud.%ud",
(addr >> 24) & 0xff, (addr >> 16) & 0xff,
(addr >> 8) & 0xff, addr & 0xff);
goto failed;
}
qident = (rn->query[0] << 8) + rn->query[1];
if (ident != qident) {
ngx_log_error(r->log_level, r->log, 0,
"wrong ident %d response for %ud.%ud.%ud.%ud, expect %d",
ident, (addr >> 24) & 0xff, (addr >> 16) & 0xff,
(addr >> 8) & 0xff, addr & 0xff, qident);
goto failed;
}
if (code) {
next = rn->waiting;
rn->waiting = NULL;
ngx_queue_remove(&rn->queue);
ngx_rbtree_delete(&r->addr_rbtree, &rn->node);
ngx_resolver_free_node(r, rn);
/* unlock addr mutex */
while (next) {
ctx = next;
ctx->state = code;
next = ctx->next;
ctx->handler(ctx);
}
return;
}
i += sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t);
if (i + 2 + sizeof(ngx_resolver_an_t) > (ngx_uint_t) n) {
goto short_response;
}
/* compression pointer to "XX.XX.XX.XX.in-addr.arpa */
if (buf[i] != 0xc0 || buf[i + 1] != 0x0c) {
err = "invalid in-addr.arpa name in DNS response";
goto invalid;
}
an = (ngx_resolver_an_t *) &buf[i + 2];
qtype = (an->type_hi << 8) + an->type_lo;
qclass = (an->class_hi << 8) + an->class_lo;
len = (an->len_hi << 8) + an->len_lo;
ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
"resolver qt:%d cl:%d len:%uz", qtype, qclass, len);
i += 2 + sizeof(ngx_resolver_an_t);
if (i + len > (ngx_uint_t) n) {
goto short_response;
}
len -= 2;
if (ngx_resolver_copy(r, &name, buf, &buf[i], &buf[n]) != NGX_OK) {
return;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver an:%V", &name);
if (len != (size_t) rn->nlen || ngx_strncmp(name.data, rn->name, len) != 0)
{
ngx_resolver_free(r, rn->name);
rn->name = name.data;
name.data = ngx_resolver_dup(r, rn->name, len);
if (name.data == NULL) {
goto failed;
}
}
ngx_queue_remove(&rn->queue);
rn->valid = ngx_time() + r->valid;
rn->expire = ngx_time() + r->expire;
ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue);
next = rn->waiting;
rn->waiting = NULL;
/* unlock addr mutex */
while (next) {
ctx = next;
ctx->state = NGX_OK;
ctx->name = name;
next = ctx->next;
ctx->handler(ctx);
}
ngx_resolver_free(r, name.data);
return;
invalid_in_addr_arpa:
ngx_log_error(r->log_level, r->log, 0,
"invalid in-addr.arpa name in DNS response");
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;
size_t len;
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 */
do {
rn = (ngx_resolver_node_t *) node;
len = (name->len > (size_t) rn->nlen) ? rn->nlen : name->len;
rc = ngx_strncmp(name->data, rn->name, len);
if (rc == 0) {
return rn;
}
node = (rc < 0) ? node->left : node->right;
} while (node != sentinel && hash == node->key);
break;
}
/* 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_t *) node;
}
/* not found */
return NULL;
}
static void
ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
{
size_t len;
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_t *) node;
rn_temp = (ngx_resolver_node_t *) temp;
len = (rn->nlen > rn_temp->nlen) ? rn_temp->nlen : rn->nlen;
p = (ngx_strncmp(rn->name, rn_temp->name, len) < 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);
}
static ngx_int_t
ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
{
u_char *p, *s;
size_t len;
ngx_uint_t ident;
ngx_resolver_qs_t *qs;
ngx_resolver_query_t *query;
len = sizeof(ngx_resolver_query_t)
+ 1 + ctx->name.len + 1 + sizeof(ngx_resolver_qs_t);
p = ngx_resolver_calloc(ctx->resolver, len);
if (p == NULL) {
return NGX_ERROR;
}
rn->qlen = (u_short) len;
rn->query = p;
query = (ngx_resolver_query_t *) p;
ident = ngx_random();
ngx_log_debug2(NGX_LOG_DEBUG_CORE, ctx->resolver->log, 0,
"resolve: \"%V\" %i", &ctx->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_query_t) + 1 + ctx->name.len + 1;
qs = (ngx_resolver_qs_t *) p;
/* query type */
qs->type_hi = 0; qs->type_lo = (u_char) ctx->type;
/* IP query class */
qs->class_hi = 0; qs->class_lo = 1;
/* convert "www.example.com" to "\3www\7example\3com\0" */
len = 0;
p--;
*p-- = '\0';
for (s = ctx->name.data + ctx->name.len - 1; s >= ctx->name.data; s--) {
if (*s != '.') {
*p = *s;
len++;
} else {
*p = (u_char) len;
len = 0;
}
p--;
}
*p = (u_char) len;
return NGX_OK;
}
/* AF_INET only */
static ngx_int_t
ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
{
u_char *p, *d;
size_t len;
ngx_int_t n;
ngx_uint_t ident;
ngx_resolver_query_t *query;
len = sizeof(ngx_resolver_query_t)
+ sizeof(".255.255.255.255.in-addr.arpa.") - 1
+ sizeof(ngx_resolver_qs_t);
p = ngx_resolver_calloc(ctx->resolver, len);
if (p == NULL) {
return NGX_ERROR;
}
rn->query = p;
query = (ngx_resolver_query_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_query_t);
for (n = 0; n < 32; n += 8){
d = ngx_sprintf(&p[1], "%ud", (ctx->addr >> n) & 0xff);
*p = (u_char) (d - &p[1]);
p = d;
}
/* query type "PTR", IP query class */
ngx_memcpy(p, "\7in-addr\4arpa\0\0\14\0\1", 18);
rn->qlen = (u_short)
(p + sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t)
- 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;
ssize_t len;
ngx_uint_t i, n;
p = src;
len = -1;
/*
* 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) {
n = (n & 0x3f << 8) + *p;
p = &buf[n];
} else {
len += 1 + n;
p = &p[n];
}
if (p >= last) {
err = "name is out of response";
goto invalid;
}
}
err = "compression pointers loop";
invalid:
ngx_log_error(r->log_level, r->log, 0, err);
return NGX_ERROR;
done:
if (name == NULL) {
return NGX_OK;
}
dst = ngx_resolver_alloc(r, len);
if (dst == NULL) {
return NGX_ERROR;
}
name->data = dst;
n = *src++;
for ( ;; ) {
if (n != 0xc0) {
ngx_memcpy(dst, src, n);
dst += n;
src += n;
n = *src++;
if (n != 0) {
*dst++ = '.';
}
} else {
n = (n & 0x3f << 8) + *src;
src = &buf[n];
n = *src++;
}
if (n == 0) {
name->len = dst - name->data;
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)
{
/* 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) {
ngx_resolver_free_locked(r, rn->u.addrs);
}
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;
}
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;
}
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";
}
ngx_int_t
ngx_udp_connect(ngx_udp_connection_t *uc)
{
int rc;
ngx_int_t event;
ngx_event_t *rev, *wev;
ngx_socket_t s;
ngx_connection_t *c;
s = ngx_socket(AF_INET, SOCK_DGRAM, 0);
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, uc->log, 0, "UDP socket %d", s);
if (s == -1) {
ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
ngx_socket_n " failed");
return NGX_ERROR;
}
c = ngx_get_connection(s, uc->log);
if (c == NULL) {
if (ngx_close_socket(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
ngx_close_socket_n "failed");
}
return NGX_ERROR;
}
if (ngx_nonblocking(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
ngx_nonblocking_n " failed");
ngx_free_connection(c);
if (ngx_close_socket(s) == -1) {
ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
ngx_close_socket_n " failed");
}
return NGX_ERROR;
}
rev = c->read;
wev = c->write;
rev->log = uc->log;
wev->log = uc->log;
uc->connection = c;
c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
#if (NGX_THREADS)
/* TODO: lock event when call completion handler */
rev->lock = &c->lock;
wev->lock = &c->lock;
rev->own_lock = &c->lock;
wev->own_lock = &c->lock;
#endif
ngx_log_debug3(NGX_LOG_DEBUG_EVENT, uc->log, 0,
"connect to %V, fd:%d #%d", &uc->server, s, c->number);
rc = connect(s, uc->sockaddr, uc->socklen);
/* TODO: aio, iocp */
if (rc == -1) {
ngx_log_error(NGX_LOG_CRIT, uc->log, ngx_socket_errno,
"connect() to %V failed", &uc->server);
return NGX_ERROR;
}
/* UDP sockets are always ready to write */
wev->ready = 1;
if (ngx_add_event) {
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) {
return NGX_ERROR;
}
} else {
/* rtsig */
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
}
return NGX_OK;
}
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