utils.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2022 Felix Fietkau <nbd@nbd.name>
   4  */
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <arpa/inet.h>
   8 #include <netdb.h>
   9 #include "unetd.h"
  10
  11 int network_get_endpoint(union network_endpoint *dest, const char *str,
  12                          int default_port, int idx)
  13 {
  14         struct addrinfo hints = {
  15                 .ai_flags = AI_ADDRCONFIG,
  16                 .ai_family = AF_UNSPEC,
  17         };
  18         char *buf = strdup(str);
  19         char *host = buf, *port;
  20         struct addrinfo *ai, *ai_cur;
  21         int n_res;
  22         int ret = -1;
  23
  24         memset(dest, 0, sizeof(*dest));
  25
  26         if (*host == '[') {
  27                 host++;
  28                 port = strchr(host, ']');
  29                 if (!port)
  30                         return -1;
  31
  32                 *(port++) = 0;
  33                 if (!*port)
  34                         port = NULL;
  35                 else if (*port == ':')
  36                         port++;
  37                 else
  38                         goto out;
  39                 hints.ai_family = AF_INET6;
  40                 hints.ai_flags |= AI_NUMERICHOST;
  41         } else {
  42                 host = buf;
  43
  44                 port = strchr(host, ':');
  45                 if (port)
  46                         *(port++) = 0;
  47         }
  48
  49         if (getaddrinfo(host, port, &hints, &ai) || !ai)
  50                 goto out;
  51
  52         while (1) {
  53                 ai_cur = ai;
  54                 for (n_res = 0; ai_cur; ai_cur = ai_cur->ai_next, n_res++)
  55                         if (!idx--)
  56                                 goto found;
  57
  58                 idx %= n_res;
  59         }
  60
  61 found:
  62         if (ai_cur->ai_addrlen > sizeof(*dest))
  63                 goto out;
  64
  65         memcpy(dest, ai_cur->ai_addr, ai_cur->ai_addrlen);
  66         if (!port)
  67                 dest->in.sin_port = htons(default_port);
  68         ret = 0;
  69
  70 out:
  71         free(buf);
  72         return ret;
  73 }
  74
  75 int network_get_subnet(int af, union network_addr *addr, int *mask, const char *str)
  76 {
  77         char *buf = strdup(str);
  78         char *sep, *end;
  79         int ret = -1;
  80
  81         if (af == AF_INET6)
  82                 *mask = 128;
  83         else
  84                 *mask = 32;
  85
  86         sep = strchr(buf, '/');
  87         if (sep) {
  88                 unsigned long val;
  89
  90                 *(sep++) = 0;
  91
  92                 val = strtoul(sep, &end, 0);
  93                 if ((end && *end) || val > *mask)
  94                         goto out;
  95
  96                 *mask = val;
  97         }
  98
  99         if (inet_pton(af, buf, addr) == 1)
 100                 ret = 0;
 101
 102 out:
 103         free(buf);
 104         return ret;
 105 }
 106
 107 int network_get_local_addr(void *local, const union network_endpoint *target)
 108 {
 109         union network_endpoint ep = {};
 110         socklen_t len;
 111         int ret = -1;
 112         int fd;
 113
 114         memset(local, 0, sizeof(union network_addr));
 115         if (target->sa.sa_family == AF_INET6)
 116                 len = sizeof(ep.in6);
 117         else
 118                 len = sizeof(ep.in);
 119
 120         fd = socket(target->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 121         if (fd < 0)
 122                 return -1;
 123
 124         if (connect(fd, (const struct sockaddr *)target, len))
 125                 goto out;
 126
 127         len = sizeof(ep);
 128         if (getsockname(fd, &ep.sa, &len))
 129                 goto out;
 130
 131         if (ep.sa.sa_family == AF_INET6)
 132                 memcpy(local, &ep.in6.sin6_addr, sizeof(ep.in6.sin6_addr));
 133         else
 134                 memcpy(local, &ep.in.sin_addr, sizeof(ep.in.sin_addr));
 135         ret = 0;
 136
 137 out:
 138         close(fd);
 139         return ret;
 140 }