libc-top-half/musl/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 *out;
  20
  21         if (!host && !serv) return EAI_NONAME;
  22
  23         if (hint) {
  24                 family = hint->ai_family;
  25                 flags = hint->ai_flags;
  26                 proto = hint->ai_protocol;
  27                 socktype = hint->ai_socktype;
  28
  29                 const int mask = AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST |
  30                         AI_V4MAPPED | AI_ALL | AI_ADDRCONFIG | AI_NUMERICSERV;
  31                 if ((flags & mask) != flags)
  32                         return EAI_BADFLAGS;
  33
  34                 switch (family) {
  35                 case AF_INET:
  36                 case AF_INET6:
  37                 case AF_UNSPEC:
  38                         break;
  39                 default:
  40                         return EAI_FAMILY;
  41                 }
  42         }
  43
  44         if (flags & AI_ADDRCONFIG) {
  45                 /* Define the "an address is configured" condition for address
  46                  * families via ability to create a socket for the family plus
  47                  * routability of the loopback address for the family. */
  48                 static const struct sockaddr_in lo4 = {
  49                         .sin_family = AF_INET, .sin_port = 65535,
  50                         .sin_addr.s_addr = __BYTE_ORDER == __BIG_ENDIAN
  51                                 ? 0x7f000001 : 0x0100007f
  52                 };
  53                 static const struct sockaddr_in6 lo6 = {
  54                         .sin6_family = AF_INET6, .sin6_port = 65535,
  55                         .sin6_addr = IN6ADDR_LOOPBACK_INIT
  56                 };
  57                 int tf[2] = { AF_INET, AF_INET6 };
  58                 const void *ta[2] = { &lo4, &lo6 };
  59                 socklen_t tl[2] = { sizeof lo4, sizeof lo6 };
  60                 for (i=0; i<2; i++) {
  61                         if (family==tf[1-i]) continue;
  62                         int s = socket(tf[i], SOCK_CLOEXEC|SOCK_DGRAM,
  63                                 IPPROTO_UDP);
  64                         if (s>=0) {
  65                                 int cs;
  66                                 pthread_setcancelstate(
  67                                         PTHREAD_CANCEL_DISABLE, &cs);
  68                                 int r = connect(s, ta[i], tl[i]);
  69                                 pthread_setcancelstate(cs, 0);
  70                                 close(s);
  71                                 if (!r) continue;
  72                         }
  73                         switch (errno) {
  74                         case EADDRNOTAVAIL:
  75                         case EAFNOSUPPORT:
  76                         case EHOSTUNREACH:
  77                         case ENETDOWN:
  78                         case ENETUNREACH:
  79                                 break;
  80                         default:
  81                                 return EAI_SYSTEM;
  82                         }
  83                         if (family == tf[i]) return EAI_NONAME;
  84                         family = tf[1-i];
  85                 }
  86         }
  87
  88         nservs = __lookup_serv(ports, serv, proto, socktype, flags);
  89         if (nservs < 0) return nservs;
  90
  91         naddrs = __lookup_name(addrs, canon, host, family, flags);
  92         if (naddrs < 0) return naddrs;
  93
  94         nais = nservs * naddrs;
  95         canon_len = strlen(canon);
  96         out = calloc(1, nais * sizeof(*out) + canon_len + 1);
  97         if (!out) return EAI_MEMORY;
  98
  99         if (canon_len) {
 100                 outcanon = (void *)&out[nais];
 101                 memcpy(outcanon, canon, canon_len+1);
 102         } else {
 103                 outcanon = 0;
 104         }
 105
 106         for (k=i=0; i<naddrs; i++) for (j=0; j<nservs; j++, k++) {
 107                 out[k].slot = i;
 108                 out[k].ai = (struct addrinfo){
 109                         .ai_family = addrs[i].family,
 110                         .ai_socktype = ports[j].socktype,
 111                         .ai_protocol = ports[j].proto,
 112                         .ai_addrlen = addrs[i].family == AF_INET
 113                                 ? sizeof(struct sockaddr_in)
 114                                 : sizeof(struct sockaddr_in6),
 115                         .ai_addr = (void *)&out[k].sa,
 116                         .ai_canonname = outcanon,
 117                         .ai_next = &out[k+1].ai };
 118                 switch (addrs[i].family) {
 119                 case AF_INET:
 120                         out[k].sa.sin.sin_family = AF_INET;
 121                         out[k].sa.sin.sin_port = htons(ports[j].port);
 122                         memcpy(&out[k].sa.sin.sin_addr, &addrs[i].addr, 4);
 123                         break;
 124                 case AF_INET6:
 125                         out[k].sa.sin6.sin6_family = AF_INET6;
 126                         out[k].sa.sin6.sin6_port = htons(ports[j].port);
 127                         out[k].sa.sin6.sin6_scope_id = addrs[i].scopeid;
 128                         memcpy(&out[k].sa.sin6.sin6_addr, &addrs[i].addr, 16);
 129                         break;
 130                 }
 131         }
 132         out[0].ref = nais;
 133         out[nais-1].ai.ai_next = 0;
 134         *res = &out->ai;
 135         return 0;
 136 }