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Annotation of embedaddon/arping/src/findif_linux.c, revision 1.1.1.3

1.1       misho       1: /* arping/src/findif_linux.c
                      2:  *
1.1.1.3 ! misho       3:  *  Copyright (C) 2000-2014 Thomas Habets <thomas@habets.se>
1.1       misho       4:  *
1.1.1.3 ! misho       5:  *  This program is free software; you can redistribute it and/or modify
        !             6:  *  it under the terms of the GNU General Public License as published by
        !             7:  *  the Free Software Foundation; either version 2 of the License, or
        !             8:  *  (at your option) any later version.
1.1       misho       9:  *
1.1.1.3 ! misho      10:  *  This program is distributed in the hope that it will be useful,
1.1       misho      11:  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
1.1.1.3 ! misho      12:  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            13:  *  GNU General Public License for more details.
1.1       misho      14:  *
                     15:  *  You should have received a copy of the GNU General Public License along
                     16:  *  with this program; if not, write to the Free Software Foundation, Inc.,
                     17:  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
                     18:  */
1.1.1.2   misho      19: /**
                     20:  * Fallback to ugly solution. This should not actually be used, as
                     21:  * modern systems have getifaddrs().
                     22:  */
1.1       misho      23: #if HAVE_CONFIG_H
                     24: #include "config.h"
                     25: #endif
                     26: 
                     27: #include <stdio.h>
                     28: #include <string.h>
                     29: 
1.1.1.3 ! misho      30: #if HAVE_LIBNET_H
        !            31: #include <libnet.h>
        !            32: #endif
        !            33: 
1.1       misho      34: #include "arping.h"
                     35: 
                     36: /**
                     37:  * WARNING: non-reentrant
                     38:  */
                     39: const char *
1.1.1.2   misho      40: arping_lookupdev(uint32_t srcip,
1.1       misho      41:                  uint32_t dstip,
                     42:                  char *ebuf)
                     43: {
1.1.1.3 ! misho      44:         FILE *f = NULL;
1.1       misho      45:        static char buf[1024];
                     46:        char buf1[1024];
                     47:        char buf2[1024];
                     48:        char *p,*p2;
                     49:        int n;
                     50: 
1.1.1.3 ! misho      51:         *ebuf = 0;
        !            52: 
        !            53:         do_libnet_init(NULL, 0);
1.1       misho      54:        libnet_addr2name4_r(dstip,0,buf2,1024);
                     55:        libnet_addr2name4_r(srcip,0,buf1,1024);
                     56: 
                     57:        /*
                     58:         * Construct and run command
                     59:         */
                     60:        snprintf(buf, 1023, "/sbin/ip route get %s from %s 2>&1",
                     61:                 buf2, buf1);
                     62:        if (!(f = popen(buf, "r"))) {
1.1.1.3 ! misho      63:                 snprintf(ebuf, LIBNET_ERRBUF_SIZE,
        !            64:                          "popen(/sbin/ip): %s", strerror(errno));
1.1       misho      65:                goto failed;
                     66:        }
                     67:        if (0>(n = fread(buf, 1, sizeof(buf)-1, f))) {
1.1.1.3 ! misho      68:                 snprintf(ebuf, LIBNET_ERRBUF_SIZE,
        !            69:                          "fread(/sbin/ip): %s", strerror(errno));
1.1       misho      70:                goto failed;
                     71:        }
                     72:        buf[n] = 0;
                     73:        if (-1 == pclose(f)) {
1.1.1.3 ! misho      74:                 snprintf(ebuf, LIBNET_ERRBUF_SIZE,
        !            75:                          "pclose(/sbin/ip): %s", strerror(errno));
1.1       misho      76:                goto failed;
                     77:        }
1.1.1.3 ! misho      78:         f = NULL;
1.1       misho      79: 
                     80:        /*
                     81:         * Parse interface name
                     82:         */
1.1.1.3 ! misho      83:         const char* head = "dev ";
        !            84:         p = strstr(buf, head);
1.1       misho      85:        if (!p) {
1.1.1.3 ! misho      86:                 if (verbose) {
        !            87:                         printf("arping: /sbin/ip output: %s\n", buf);
        !            88:                 }
        !            89:                 snprintf(ebuf, LIBNET_ERRBUF_SIZE,
        !            90:                          "\"dev \" not found in /sbin/ip output.");
1.1       misho      91:                goto failed;
                     92:        }
                     93: 
1.1.1.3 ! misho      94:         p += strlen(head);
1.1       misho      95: 
                     96:        p2 = strchr(p, ' ');
                     97:        if (!p2) {
1.1.1.3 ! misho      98:                 if (verbose) {
        !            99:                         printf("arping: /sbin/ip output: %s\n", buf);
        !           100:                 }
        !           101:                 snprintf(ebuf, LIBNET_ERRBUF_SIZE,
        !           102:                          "interface not found in /sbin/ip output.");
1.1       misho     103:                goto failed;
                    104:        }
                    105:        *p2 = 0;
                    106:        return p;
                    107:  failed:
1.1.1.3 ! misho     108:         if (f) {
        !           109:                 pclose(f);
        !           110:         }
1.1.1.2   misho     111:        return NULL;
1.1       misho     112: }
1.1.1.2   misho     113: /* ---- Emacs Variables ----
                    114:  * Local Variables:
                    115:  * c-basic-offset: 8
                    116:  * indent-tabs-mode: nil
                    117:  * End:
                    118:  */