utils.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2022 Felix Fietkau <nbd@nbd.name>
   4  */
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <sys/stat.h>
   8 #include <arpa/inet.h>
   9 #include <netdb.h>
  10 #include <stdio.h>
  11 #include "unetd.h"
  12
  13 int network_get_endpoint(union network_endpoint *dest, const char *str,
  14                          int default_port, int idx)
  15 {
  16         struct addrinfo hints = {
  17                 .ai_flags = AI_ADDRCONFIG,
  18                 .ai_family = AF_UNSPEC,
  19         };
  20         char *buf = strdup(str);
  21         char *host = buf, *port;
  22         struct addrinfo *ai, *ai_cur;
  23         int n_res;
  24         int ret = -1;
  25
  26         memset(dest, 0, sizeof(*dest));
  27
  28         if (*host == '[') {
  29                 host++;
  30                 port = strchr(host, ']');
  31                 if (!port)
  32                         goto out;
  33
  34                 *(port++) = 0;
  35                 if (!*port)
  36                         port = NULL;
  37                 else if (*port == ':')
  38                         port++;
  39                 else
  40                         goto out;
  41                 hints.ai_family = AF_INET6;
  42                 hints.ai_flags |= AI_NUMERICHOST;
  43         } else {
  44                 host = buf;
  45
  46                 port = strchr(host, ':');
  47                 if (port)
  48                         *(port++) = 0;
  49         }
  50
  51         if (getaddrinfo(host, port, &hints, &ai) || !ai)
  52                 goto out;
  53
  54         while (1) {
  55                 ai_cur = ai;
  56                 for (n_res = 0; ai_cur; ai_cur = ai_cur->ai_next, n_res++)
  57                         if (!idx--)
  58                                 goto found;
  59
  60                 idx %= n_res;
  61         }
  62
  63 found:
  64         if (ai_cur->ai_addrlen > sizeof(*dest))
  65                 goto free_ai;
  66
  67         memcpy(dest, ai_cur->ai_addr, ai_cur->ai_addrlen);
  68         if (!port)
  69                 dest->in.sin_port = htons(default_port);
  70         ret = 0;
  71
  72 free_ai:
  73         freeaddrinfo(ai);
  74
  75 out:
  76         free(buf);
  77         return ret;
  78 }
  79
  80 int network_get_subnet(int af, union network_addr *addr, int *mask, const char *str)
  81 {
  82         char *buf = strdup(str);
  83         char *sep, *end;
  84         int ret = -1;
  85
  86         if (af == AF_INET6)
  87                 *mask = 128;
  88         else
  89                 *mask = 32;
  90
  91         sep = strchr(buf, '/');
  92         if (sep) {
  93                 unsigned long val;
  94
  95                 *(sep++) = 0;
  96
  97                 val = strtoul(sep, &end, 0);
  98                 if ((end && *end) || val > *mask)
  99                         goto out;
 100
 101                 *mask = val;
 102         }
 103
 104         if (inet_pton(af, buf, addr) == 1)
 105                 ret = 0;
 106
 107 out:
 108         free(buf);
 109         return ret;
 110 }
 111
 112 int network_get_local_addr(void *local, const union network_endpoint *target)
 113 {
 114         union network_endpoint ep = {};
 115         socklen_t len;
 116         int ret = -1;
 117         int fd;
 118
 119         memset(local, 0, sizeof(union network_addr));
 120         if (target->sa.sa_family == AF_INET6)
 121                 len = sizeof(ep.in6);
 122         else
 123                 len = sizeof(ep.in);
 124
 125         fd = socket(target->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 126         if (fd < 0)
 127                 return -1;
 128
 129         if (connect(fd, (const struct sockaddr *)target, len))
 130                 goto out;
 131
 132         len = sizeof(ep);
 133         if (getsockname(fd, &ep.sa, &len))
 134                 goto out;
 135
 136         if (ep.sa.sa_family == AF_INET6)
 137                 memcpy(local, &ep.in6.sin6_addr, sizeof(ep.in6.sin6_addr));
 138         else
 139                 memcpy(local, &ep.in.sin_addr, sizeof(ep.in.sin_addr));
 140         ret = 0;
 141
 142 out:
 143         close(fd);
 144         return ret;
 145 }
 146
 147 void *unet_read_file(const char *name, size_t *len)
 148 {
 149         struct stat st;
 150         void *data;
 151         FILE *f;
 152
 153         f = fopen(name, "r");
 154         if (!f)
 155                 goto error;
 156
 157         if (fstat(fileno(f), &st) < 0)
 158                 goto close;
 159
 160         if (*len && st.st_size > *len)
 161                 goto close;
 162
 163         data = malloc(st.st_size);
 164         if (!data)
 165                 goto close;
 166
 167         if (fread(data, 1, st.st_size, f) != st.st_size) {
 168                 free(data);
 169                 goto close;
 170         }
 171         fclose(f);
 172
 173         *len = st.st_size;
 174         return data;
 175
 176 close:
 177         fclose(f);
 178 error:
 179         *len = 0;
 180         return NULL;
 181 }