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Resolver: improved code readability.
Renamed ngx_resolver_query_t to ngx_resolver_hdr_t as it describes the header that is common to DNS queries and answers. Replaced the magic number 12 by the size of the header structure. The other changes are self-explanatory.
This commit is contained in:
Ruslan Ermilov
parent
0c585adfd4
commit
3d245d4792
@ -26,7 +26,7 @@ typedef struct {
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u_char nns_lo;
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u_char nar_hi;
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u_char nar_lo;
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} ngx_resolver_query_t;
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} ngx_resolver_hdr_t;
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typedef struct {
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@ -1021,31 +1021,31 @@ ngx_resolver_read_response(ngx_event_t *rev)
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static void
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ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
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{
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char *err;
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size_t len;
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ngx_uint_t i, times, ident, qident, flags, code, nqs, nan,
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qtype, qclass;
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ngx_queue_t *q;
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ngx_resolver_qs_t *qs;
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ngx_resolver_node_t *rn;
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ngx_resolver_query_t *query;
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char *err;
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size_t len;
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ngx_uint_t i, times, ident, qident, flags, code, nqs, nan,
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qtype, qclass;
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ngx_queue_t *q;
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ngx_resolver_qs_t *qs;
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ngx_resolver_hdr_t *response;
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ngx_resolver_node_t *rn;
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if ((size_t) n < sizeof(ngx_resolver_query_t)) {
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if (n < sizeof(ngx_resolver_hdr_t)) {
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goto short_response;
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}
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query = (ngx_resolver_query_t *) buf;
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response = (ngx_resolver_hdr_t *) buf;
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ident = (query->ident_hi << 8) + query->ident_lo;
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flags = (query->flags_hi << 8) + query->flags_lo;
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nqs = (query->nqs_hi << 8) + query->nqs_lo;
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nan = (query->nan_hi << 8) + query->nan_lo;
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ident = (response->ident_hi << 8) + response->ident_lo;
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flags = (response->flags_hi << 8) + response->flags_lo;
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nqs = (response->nqs_hi << 8) + response->nqs_lo;
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nan = (response->nan_hi << 8) + response->nan_lo;
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ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0,
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"resolver DNS response %ui fl:%04Xui %ui/%ui/%ud/%ud",
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ident, flags, nqs, nan,
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(query->nns_hi << 8) + query->nns_lo,
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(query->nar_hi << 8) + query->nar_lo);
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(response->nns_hi << 8) + response->nns_lo,
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(response->nar_hi << 8) + response->nar_lo);
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if (!(flags & 0x8000)) {
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ngx_log_error(r->log_level, r->log, 0,
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@ -1087,7 +1087,7 @@ ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
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goto done;
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}
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i = sizeof(ngx_resolver_query_t);
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i = sizeof(ngx_resolver_hdr_t);
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while (i < (ngx_uint_t) n) {
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if (buf[i] == '\0') {
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@ -1152,7 +1152,7 @@ found:
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short_response:
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err = "short dns response";
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err = "short DNS response";
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done:
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@ -1180,12 +1180,15 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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uint32_t hash;
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in_addr_t addr, *addrs;
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ngx_str_t name;
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ngx_uint_t qtype, qident, naddrs, a, i, n, start;
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ngx_uint_t type, qident, naddrs, a, i, n, start;
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ngx_resolver_an_t *an;
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ngx_resolver_ctx_t *ctx, *next;
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ngx_resolver_node_t *rn;
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if (ngx_resolver_copy(r, &name, buf, &buf[12], &buf[last]) != NGX_OK) {
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if (ngx_resolver_copy(r, &name, buf,
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buf + sizeof(ngx_resolver_hdr_t), buf + last)
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!= NGX_OK)
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{
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return;
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}
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@ -1215,7 +1218,7 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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ngx_resolver_free(r, name.data);
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if (code == 0 && nan == 0) {
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code = 3; /* NXDOMAIN */
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code = NGX_RESOLVE_NXDOMAIN;
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}
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if (code) {
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@ -1246,7 +1249,6 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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addr = 0;
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addrs = NULL;
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cname = NULL;
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qtype = 0;
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ttl = 0;
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for (a = 0; a < nan; a++) {
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@ -1273,7 +1275,7 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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test_length:
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if (i - start < 2) {
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err = "invalid name in dns response";
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err = "invalid name in DNS response";
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goto invalid;
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}
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@ -1285,7 +1287,7 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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an = (ngx_resolver_an_t *) &buf[i];
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qtype = (an->type_hi << 8) + an->type_lo;
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type = (an->type_hi << 8) + an->type_lo;
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len = (an->len_hi << 8) + an->len_lo;
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ttl = (an->ttl[0] << 24) + (an->ttl[1] << 16)
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+ (an->ttl[2] << 8) + (an->ttl[3]);
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@ -1294,7 +1296,9 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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ttl = 0;
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}
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if (qtype == NGX_RESOLVE_A) {
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switch (type) {
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case NGX_RESOLVE_A:
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i += sizeof(ngx_resolver_an_t);
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@ -1309,16 +1313,25 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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i += len;
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} else if (qtype == NGX_RESOLVE_CNAME) {
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break;
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case NGX_RESOLVE_CNAME:
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cname = &buf[i] + sizeof(ngx_resolver_an_t);
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i += sizeof(ngx_resolver_an_t) + len;
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} else if (qtype == NGX_RESOLVE_DNAME) {
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break;
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case NGX_RESOLVE_DNAME:
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i += sizeof(ngx_resolver_an_t) + len;
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} else {
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break;
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default:
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ngx_log_error(r->log_level, r->log, 0,
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"unexpected qtype %ui", qtype);
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"unexpected RR type %ui", type);
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}
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}
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@ -1347,27 +1360,25 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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if (buf[i] & 0xc0) {
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i += 2;
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goto ok;
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break;
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}
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if (buf[i] == 0) {
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i++;
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goto ok;
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break;
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}
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i += 1 + buf[i];
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}
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ok:
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an = (ngx_resolver_an_t *) &buf[i];
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qtype = (an->type_hi << 8) + an->type_lo;
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type = (an->type_hi << 8) + an->type_lo;
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len = (an->len_hi << 8) + an->len_lo;
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i += sizeof(ngx_resolver_an_t);
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if (qtype == NGX_RESOLVE_A) {
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if (type == NGX_RESOLVE_A) {
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addrs[n++] = htonl((buf[i] << 24) + (buf[i + 1] << 16)
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+ (buf[i + 2] << 8) + (buf[i + 3]));
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@ -1422,12 +1433,13 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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rn->query = NULL;
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return;
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}
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} else if (cname) {
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if (cname) {
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/* CNAME only */
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if (ngx_resolver_copy(r, &name, buf, cname, &buf[last]) != NGX_OK) {
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if (ngx_resolver_copy(r, &name, buf, cname, buf + last) != NGX_OK) {
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return;
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}
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@ -1460,13 +1472,12 @@ ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
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}
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ngx_log_error(r->log_level, r->log, 0,
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"no A or CNAME types in DNS responses, unknown query type: %ui",
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qtype);
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"no A or CNAME types in DNS response");
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return;
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short_response:
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err = "short dns response";
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err = "short DNS response";
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invalid:
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@ -1494,29 +1505,32 @@ ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
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size_t len;
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in_addr_t addr;
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int32_t ttl;
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ngx_int_t digit;
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ngx_int_t octet;
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ngx_str_t name;
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ngx_uint_t i, mask, qident;
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ngx_resolver_an_t *an;
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ngx_resolver_ctx_t *ctx, *next;
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ngx_resolver_node_t *rn;
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if (ngx_resolver_copy(r, NULL, buf, &buf[12], &buf[n]) != NGX_OK) {
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if (ngx_resolver_copy(r, NULL, buf,
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buf + sizeof(ngx_resolver_hdr_t), buf + n)
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!= NGX_OK)
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{
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goto invalid_in_addr_arpa;
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}
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addr = 0;
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i = 12;
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i = sizeof(ngx_resolver_hdr_t);
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for (mask = 0; mask < 32; mask += 8) {
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len = buf[i++];
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digit = ngx_atoi(&buf[i], len);
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if (digit == NGX_ERROR || digit > 255) {
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octet = ngx_atoi(&buf[i], len);
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if (octet == NGX_ERROR || octet > 255) {
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goto invalid_in_addr_arpa;
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}
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addr += digit << mask;
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addr += octet << mask;
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i += len;
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}
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@ -1547,7 +1561,7 @@ ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
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}
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if (code == 0 && nan == 0) {
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code = 3; /* NXDOMAIN */
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code = NGX_RESOLVE_NXDOMAIN;
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}
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if (code) {
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@ -1581,7 +1595,7 @@ ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
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/* compression pointer to "XX.XX.XX.XX.in-addr.arpa */
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if (buf[i] != 0xc0 || buf[i + 1] != 0x0c) {
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if (buf[i] != 0xc0 || buf[i + 1] != sizeof(ngx_resolver_hdr_t)) {
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err = "invalid in-addr.arpa name in DNS response";
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goto invalid;
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}
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@ -1607,7 +1621,7 @@ ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
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goto short_response;
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}
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if (ngx_resolver_copy(r, &name, buf, &buf[i], &buf[n]) != NGX_OK) {
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if (ngx_resolver_copy(r, &name, buf, buf + i, buf + n) != NGX_OK) {
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return;
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}
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@ -1796,15 +1810,15 @@ ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
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static ngx_int_t
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ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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{
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u_char *p, *s;
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size_t len, nlen;
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ngx_uint_t ident;
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ngx_resolver_qs_t *qs;
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ngx_resolver_query_t *query;
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u_char *p, *s;
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size_t len, nlen;
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ngx_uint_t ident;
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ngx_resolver_qs_t *qs;
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ngx_resolver_hdr_t *query;
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nlen = ctx->name.len ? (1 + ctx->name.len + 1) : 1;
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len = sizeof(ngx_resolver_query_t) + nlen + sizeof(ngx_resolver_qs_t);
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len = sizeof(ngx_resolver_hdr_t) + nlen + sizeof(ngx_resolver_qs_t);
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p = ngx_resolver_alloc(ctx->resolver, len);
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if (p == NULL) {
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@ -1814,7 +1828,7 @@ ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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rn->qlen = (u_short) len;
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rn->query = p;
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query = (ngx_resolver_query_t *) p;
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query = (ngx_resolver_hdr_t *) p;
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ident = ngx_random();
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@ -1833,14 +1847,14 @@ ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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query->nns_hi = 0; query->nns_lo = 0;
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query->nar_hi = 0; query->nar_lo = 0;
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p += sizeof(ngx_resolver_query_t) + nlen;
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p += sizeof(ngx_resolver_hdr_t) + nlen;
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qs = (ngx_resolver_qs_t *) p;
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/* query type */
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qs->type_hi = 0; qs->type_lo = (u_char) ctx->type;
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/* IP query class */
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/* IN query class */
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qs->class_hi = 0; qs->class_lo = 1;
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/* convert "www.example.com" to "\3www\7example\3com\0" */
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@ -1885,13 +1899,13 @@ ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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static ngx_int_t
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ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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{
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u_char *p, *d;
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size_t len;
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ngx_int_t n;
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ngx_uint_t ident;
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ngx_resolver_query_t *query;
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u_char *p, *d;
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size_t len;
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ngx_int_t n;
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ngx_uint_t ident;
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ngx_resolver_hdr_t *query;
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len = sizeof(ngx_resolver_query_t)
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len = sizeof(ngx_resolver_hdr_t)
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+ sizeof(".255.255.255.255.in-addr.arpa.") - 1
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+ sizeof(ngx_resolver_qs_t);
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@ -1901,7 +1915,7 @@ ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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}
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rn->query = p;
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query = (ngx_resolver_query_t *) p;
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query = (ngx_resolver_hdr_t *) p;
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ident = ngx_random();
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@ -1917,7 +1931,7 @@ ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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query->nns_hi = 0; query->nns_lo = 0;
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query->nar_hi = 0; query->nar_lo = 0;
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p += sizeof(ngx_resolver_query_t);
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p += sizeof(ngx_resolver_hdr_t);
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for (n = 0; n < 32; n += 8) {
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d = ngx_sprintf(&p[1], "%ud", (ctx->addr >> n) & 0xff);
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@ -1925,7 +1939,7 @@ ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
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p = d;
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}
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/* query type "PTR", IP query class */
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/* query type "PTR", IN query class */
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ngx_memcpy(p, "\7in-addr\4arpa\0\0\14\0\1", 18);
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rn->qlen = (u_short)
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