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Member "trafshow-3.1/getarptab.c" of archive trafshow-3.1.tgz:
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1 /*
2 * Copyright (c) 1998 JSC Rinet, Novosibirsk, Russia
3 *
4 * Redistribution and use in source forms, with and without modification,
5 * are permitted provided that this entire comment appears intact.
6 * Redistribution in binary form may occur without any restrictions.
7 *
8 * THIS SOFTWARE IS PROVIDED ``AS IS'' WITHOUT ANY WARRANTIES OF ANY KIND.
9 */
10
11 /* getarptab.c -- translate MAC addresses to IP addresses using ARP table */
12
13 #ifdef HAVE_CONFIG_H
14 #include <config.h>
15 #endif
16
17 #ifdef HAVE_RTF_LLINFO /* BSD systems */
18
19 #include <sys/param.h>
20 #include <sys/types.h>
21 #include <sys/socket.h>
22 #include <sys/sysctl.h>
23
24 #include <net/if.h>
25 #include <net/if_dl.h>
26 #include <net/route.h>
27 #include <netinet/in.h>
28 #include <netinet/if_ether.h>
29
30 #ifdef ETHER_ADDR_LEN
31 #define MAC_ADDR_LEN ETHER_ADDR_LEN
32 #else
33 #define MAC_ADDR_LEN 6
34 #endif
35
36 u_char *
37 getarptab(ep)
38 u_char *ep;
39 {
40 int mib[6];
41 size_t needed;
42 char *lim, *buf, *next;
43 struct rt_msghdr *rtm;
44 static struct sockaddr_inarp *sin;
45 struct sockaddr_dl *sdl;
46
47 mib[0] = CTL_NET;
48 mib[1] = PF_ROUTE;
49 mib[2] = 0;
50 mib[3] = AF_INET;
51 mib[4] = NET_RT_FLAGS;
52 mib[5] = RTF_LLINFO;
53 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
54 error(1, "getarptab: sysctl");
55 if ((buf = (char *)malloc(needed)) == NULL)
56 error(1, "getarptab: malloc");
57 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
58 error(1, "getarptab: sysctl");
59 lim = buf + needed;
60 for (next = buf; next < lim; next += rtm->rtm_msglen) {
61 rtm = (struct rt_msghdr *)next;
62 sin = (struct sockaddr_inarp *)(rtm + 1);
63 sdl = (struct sockaddr_dl *)(sin + 1);
64 if (sdl->sdl_alen &&
65 !memcmp(ep, (u_char *)LLADDR(sdl), MAC_ADDR_LEN)) {
66 free(buf);
67 return ((u_char *)&sin->sin_addr);
68 }
69 }
70 free(buf);
71 return (u_char *)0;
72 }
73
74 #elif HAVE_PROC_NET_ARP /* Linux systems */
75
76 #include <sys/types.h>
77 #include <netinet/in.h>
78 #include <arpa/inet.h>
79 #include <stdio.h>
80 #include <string.h>
81
82 u_char *
83 getarptab(ep)
84 u_char *ep;
85 {
86 FILE *fp;
87 char *req, *ip, *mac, buf[100];
88 static struct in_addr addr;
89
90 if ((fp = fopen("/proc/net/arp", "r")) != NULL) {
91 req = (char *)entoa(ep);
92 while (fgets(buf, sizeof(buf), fp) != NULL) {
93 buf[sizeof(buf)-1] = '\0';
94 if ((ip = strtok(buf, " \t")) == NULL)
95 continue;
96 while ((mac = strtok(NULL, " \t")) != NULL) {
97 if (!strcasecmp(req, mac)) {
98 if (inet_aton(ip, &addr)) {
99 (void) fclose(fp);
100 return ((u_char *)&addr);
101 }
102 break;
103 }
104 }
105 }
106 (void) fclose(fp);
107 }
108 return (u_char *)0;
109 }
110
111 #else /* XXX. Get ARP table not implemented yet for SYSV systems */
112
113 u_char *
114 getarptab(ep)
115 u_char *ep;
116 {
117 return (u_char *)0;
118 }
119
120 #endif