nsz Git - musl/blob - src/network/getaddrinfo.c

   1 #include <stdlib.h>
   2 #include <sys/socket.h>
   3 #include <netinet/in.h>
   4 #include <netdb.h>
   5 #include <string.h>
   6 #include <pthread.h>
   7 #include <unistd.h>
   8 #include <endian.h>
   9 #include <errno.h>
  10 #include "lookup.h"
  11
  12 int getaddrinfo(const char *restrict host, const char *restrict serv, const struct addrinfo *restrict hint, struct addrinfo **restrict res)
  13 {
  14         struct service ports[MAXSERVS];
  15         struct address addrs[MAXADDRS];
  16         char canon[256], *outcanon;
  17         int nservs, naddrs, nais, canon_len, i, j, k;
  18         int family = AF_UNSPEC, flags = 0, proto = 0, socktype = 0;
  19         struct aibuf {
  20                 struct addrinfo ai;
  21                 union sa {
  22                         struct sockaddr_in sin;
  23                         struct sockaddr_in6 sin6;
  24                 } sa;
  25         } *out;
  26
  27         if (!host && !serv) return EAI_NONAME;
  28
  29         if (hint) {
  30                 family = hint->ai_family;
  31                 flags = hint->ai_flags;
  32                 proto = hint->ai_protocol;
  33                 socktype = hint->ai_socktype;
  34
  35                 const int mask = AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST |
  36                         AI_V4MAPPED | AI_ALL | AI_ADDRCONFIG | AI_NUMERICSERV;
  37                 if ((flags & mask) != flags)
  38                         return EAI_BADFLAGS;
  39
  40                 switch (family) {
  41                 case AF_INET:
  42                 case AF_INET6:
  43                 case AF_UNSPEC:
  44                         break;
  45                 default:
  46                         return EAI_FAMILY;
  47                 }
  48         }
  49
  50         if (flags & AI_ADDRCONFIG) {
  51                 /* Define the "an address is configured" condition for address
  52                  * families via ability to create a socket for the family plus
  53                  * routability of the loopback address for the family. */
  54                 static const struct sockaddr_in lo4 = {
  55                         .sin_family = AF_INET, .sin_port = 65535,
  56                         .sin_addr.s_addr = __BYTE_ORDER == __BIG_ENDIAN
  57                                 ? 0x7f000001 : 0x0100007f
  58                 };
  59                 static const struct sockaddr_in6 lo6 = {
  60                         .sin6_family = AF_INET6, .sin6_port = 65535,
  61                         .sin6_addr = IN6ADDR_LOOPBACK_INIT
  62                 };
  63                 int tf[2] = { AF_INET, AF_INET6 };
  64                 const void *ta[2] = { &lo4, &lo6 };
  65                 socklen_t tl[2] = { sizeof lo4, sizeof lo6 };
  66                 for (i=0; i<2; i++) {
  67                         if (family==tf[1-i]) continue;
  68                         int s = socket(tf[i], SOCK_CLOEXEC|SOCK_DGRAM,
  69                                 IPPROTO_UDP);
  70                         if (s>=0) {
  71                                 int cs;
  72                                 pthread_setcancelstate(
  73                                         PTHREAD_CANCEL_DISABLE, &cs);
  74                                 int r = connect(s, ta[i], tl[i]);
  75                                 pthread_setcancelstate(cs, 0);
  76                                 close(s);
  77                                 if (!r) continue;
  78                         }
  79                         if (errno != EAFNOSUPPORT) return EAI_SYSTEM;
  80                         if (family == tf[i]) return EAI_NONAME;
  81                         family = tf[1-i];
  82                 }
  83         }
  84
  85         nservs = __lookup_serv(ports, serv, proto, socktype, flags);
  86         if (nservs < 0) return nservs;
  87
  88         naddrs = __lookup_name(addrs, canon, host, family, flags);
  89         if (naddrs < 0) return naddrs;
  90
  91         nais = nservs * naddrs;
  92         canon_len = strlen(canon);
  93         out = calloc(1, nais * sizeof(*out) + canon_len + 1);
  94         if (!out) return EAI_MEMORY;
  95
  96         if (canon_len) {
  97                 outcanon = (void *)&out[nais];
  98                 memcpy(outcanon, canon, canon_len+1);
  99         } else {
 100                 outcanon = 0;
 101         }
 102
 103         for (k=i=0; i<naddrs; i++) for (j=0; j<nservs; j++, k++) {
 104                 out[k].ai = (struct addrinfo){
 105                         .ai_family = addrs[i].family,
 106                         .ai_socktype = ports[j].socktype,
 107                         .ai_protocol = ports[j].proto,
 108                         .ai_addrlen = addrs[i].family == AF_INET
 109                                 ? sizeof(struct sockaddr_in)
 110                                 : sizeof(struct sockaddr_in6),
 111                         .ai_addr = (void *)&out[k].sa,
 112                         .ai_canonname = outcanon,
 113                         .ai_next = &out[k+1].ai };
 114                 switch (addrs[i].family) {
 115                 case AF_INET:
 116                         out[k].sa.sin.sin_family = AF_INET;
 117                         out[k].sa.sin.sin_port = htons(ports[j].port);
 118                         memcpy(&out[k].sa.sin.sin_addr, &addrs[i].addr, 4);
 119                         break;
 120                 case AF_INET6:
 121                         out[k].sa.sin6.sin6_family = AF_INET6;
 122                         out[k].sa.sin6.sin6_port = htons(ports[j].port);
 123                         out[k].sa.sin6.sin6_scope_id = addrs[i].scopeid;
 124                         memcpy(&out[k].sa.sin6.sin6_addr, &addrs[i].addr, 16);
 125                         break;
 126                 }
 127         }
 128         out[nais-1].ai.ai_next = 0;
 129         *res = &out->ai;
 130         return 0;
 131 }