source: EcnlProtoTool/trunk/musl-1.1.18/src/network/res_msend.c@ 444

Last change on this file since 444 was 444, checked in by coas-nagasima, 4 years ago

muslのソースコードを追加
  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/x-csrc;charset=UTF-8
File size: 4.9 KB
Line 
1#include <sys/socket.h>
2#include <netinet/in.h>
3#include <netdb.h>
4#include <arpa/inet.h>
5#include <stdint.h>
6#include <string.h>
7#include <poll.h>
8#include <time.h>
9#include <ctype.h>
10#include <unistd.h>
11#include <errno.h>
12#include <pthread.h>
13#include "stdio_impl.h"
14#include "syscall.h"
15#include "lookup.h"
16
17static void cleanup(void *p)
18{
19 __syscall(SYS_close, (intptr_t)p);
20}
21
22static unsigned long mtime()
23{
24 struct timespec ts;
25 clock_gettime(CLOCK_REALTIME, &ts);
26 return (unsigned long)ts.tv_sec * 1000
27 + ts.tv_nsec / 1000000;
28}
29
30int __res_msend_rc(int nqueries, const unsigned char *const *queries,
31 const int *qlens, unsigned char *const *answers, int *alens, int asize,
32 const struct resolvconf *conf)
33{
34 int fd;
35 int timeout, attempts, retry_interval, servfail_retry;
36 union {
37 struct sockaddr_in sin;
38 struct sockaddr_in6 sin6;
39 } sa = {0}, ns[MAXNS] = {{0}};
40 socklen_t sl = sizeof sa.sin;
41 int nns = 0;
42 int family = AF_INET;
43 int rlen;
44 int next;
45 int i;
46 int cs;
47 struct pollfd pfd;
48 unsigned long t0, t1, t2;
49 int ret = -1;
50
51 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
52
53 timeout = 1000*conf->timeout;
54 attempts = conf->attempts;
55
56 for (nns=0; nns<conf->nns; nns++) {
57 const struct address *iplit = &conf->ns[nns];
58 if (iplit->family == AF_INET) {
59 memcpy(&ns[nns].sin.sin_addr, iplit->addr, 4);
60 ns[nns].sin.sin_port = htons(53);
61 ns[nns].sin.sin_family = AF_INET;
62 } else {
63 sl = sizeof sa.sin6;
64 memcpy(&ns[nns].sin6.sin6_addr, iplit->addr, 16);
65 ns[nns].sin6.sin6_port = htons(53);
66 ns[nns].sin6.sin6_scope_id = iplit->scopeid;
67 ns[nns].sin6.sin6_family = family = AF_INET6;
68 }
69
70 /* Get local address and open/bind a socket */
71 sa.sin.sin_family = family;
72 fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
73
74 /* Handle case where system lacks IPv6 support */
75 if (fd < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
76 fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
77 family = AF_INET;
78 }
79 if (fd < 0 || bind(fd, (void *)&sa, sl) < 0) {
80 if (fd >= 0) close(fd);
81 continue;
82 }
83 ret = 0;
84
85 /* Past this point, there are no errors. Each individual query will
86 * yield either no reply (indicated by zero length) or an answer
87 * packet which is up to the caller to interpret. */
88
89 pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
90 pthread_setcancelstate(cs, 0);
91
92 /* Convert any IPv4 addresses in a mixed environment to v4-mapped */
93 if (family == AF_INET6) {
94 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0);
95 i=nns;
96 if (ns[i].sin.sin_family != AF_INET) goto out;
97 memcpy(ns[i].sin6.sin6_addr.s6_addr+12,
98 &ns[i].sin.sin_addr, 4);
99 memcpy(ns[i].sin6.sin6_addr.s6_addr,
100 "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
101 ns[i].sin6.sin6_family = AF_INET6;
102 ns[i].sin6.sin6_flowinfo = 0;
103 ns[i].sin6.sin6_scope_id = 0;
104 }
105
106 memset(alens, 0, sizeof *alens * nqueries);
107
108 pfd.fd = fd;
109 pfd.events = POLLIN;
110 retry_interval = timeout / attempts;
111 next = 0;
112 t0 = t2 = mtime();
113 t1 = t2 - retry_interval;
114
115 for (; t2-t0 < timeout; t2=mtime()) {
116 if (t2-t1 >= retry_interval) {
117 /* Query all configured namservers in parallel */
118 for (i=0; i<nqueries; i++)
119 if (!alens[i])
120 sendto(fd, queries[i],
121 qlens[i], MSG_NOSIGNAL,
122 (void *)&ns[nns], sl);
123 t1 = t2;
124 servfail_retry = 2 * nqueries;
125 }
126
127 /* Wait for a response, or until time to retry */
128 if (poll(&pfd, 1, t1+retry_interval-t2) <= 0) continue;
129
130 while ((rlen = recvfrom(fd, answers[next], asize, 0,
131 (void *)&sa, (socklen_t[1]){sl})) >= 0) {
132
133 /* Ignore non-identifiable packets */
134 if (rlen < 4) continue;
135
136 /* Ignore replies from addresses we didn't send to */
137 if (memcmp(ns + nns, &sa, sl) != 0) continue;
138
139 /* Find which query this answer goes with, if any */
140 for (i=next; i<nqueries && (
141 answers[next][0] != queries[i][0] ||
142 answers[next][1] != queries[i][1] ); i++);
143 if (i==nqueries) continue;
144 if (alens[i]) continue;
145
146 /* Only accept positive or negative responses;
147 * retry immediately on server failure, and ignore
148 * all other codes such as refusal. */
149 switch (answers[next][3] & 15) {
150 case 0:
151 case 3:
152 break;
153 case 2:
154 if (servfail_retry && servfail_retry--)
155 sendto(fd, queries[i],
156 qlens[i], MSG_NOSIGNAL,
157 (void *)&ns[nns], sl);
158 default:
159 continue;
160 }
161
162 /* Store answer in the right slot, or update next
163 * available temp slot if it's already in place. */
164 alens[i] = rlen;
165 if (i == next)
166 for (; next<nqueries && alens[next]; next++);
167 else
168 memcpy(answers[i], answers[next], rlen);
169
170 if (next == nqueries) goto out;
171 }
172 }
173 out:
174 pthread_cleanup_pop(1);
175 }
176 return ret;
177}
178
179int __res_msend(int nqueries, const unsigned char *const *queries,
180 const int *qlens, unsigned char *const *answers, int *alens, int asize)
181{
182 struct resolvconf conf;
183 if (__get_resolv_conf(&conf, 0, 0) < 0) return -1;
184 return __res_msend_rc(nqueries, queries, qlens, answers, alens, asize, &conf);
185}
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