xref: /third_party/toybox/toys/pending/arp.c (revision 0f66f451) 
1/* arp.c - manipulate the system ARP cache
2 *
3 * Copyright 2014 Sandeep Sharma <sandeep.jack2756@gmail.com>
4 * Copyright 2014 Kyungwan Han <asura321@gamil.com>
5 * No Standard
6
7USE_ARP(NEWTOY(arp, "vi:nDsdap:A:H:[+Ap][!sd]", TOYFLAG_USR|TOYFLAG_BIN))
8
9config ARP
10  bool "arp"
11  default n
12  help
13    usage: arp
14    [-vn] [-H HWTYPE] [-i IF] -a [HOSTNAME]
15    [-v]              [-i IF] -d HOSTNAME [pub]
16    [-v]  [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [temp]
17    [-v]  [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [netmask MASK] pub
18    [-v]  [-H HWTYPE] [-i IF] -Ds HOSTNAME IFACE [netmask MASK] pub
19
20    Manipulate ARP cache.
21
22    -a	Display (all) hosts
23    -s	Set new ARP entry
24    -d	Delete a specified entry
25    -v	Verbose
26    -n	Don't resolve names
27    -i IFACE	Network interface
28    -D	Read <hwaddr> from given device
29    -A,-p AF	Protocol family
30    -H HWTYPE	Hardware address type
31
32*/
33
34#define FOR_arp
35#include "toys.h"
36#include <net/if_arp.h>
37
38GLOBALS(
39    char *hw_type;
40    char *af_type_A;
41    char *af_type_p;
42    char *interface;
43
44    int sockfd;
45    char *device;
46)
47
48struct arpreq req;
49
50struct type {
51  char *name;
52  int val;
53};
54
55struct type hwtype[] = {
56  {"ether", ARPHRD_ETHER },
57  {"loop" ,ARPHRD_LOOPBACK},
58  {"ppp" ,ARPHRD_PPP},
59  {"infiniband" ,ARPHRD_INFINIBAND},
60  {NULL, -1},
61};
62
63struct type aftype[] = {
64  {"inet", AF_INET },
65  {"inet6" ,AF_INET6},
66  {"unspec" ,AF_UNSPEC},
67  {NULL, -1},
68};
69
70struct type flag_type[] = {
71  {"PERM", ATF_PERM },
72  {"PUB" ,ATF_PUBL},
73  {"DONTPUB" ,ATF_DONTPUB},
74  {"TRAIL" ,ATF_USETRAILERS},
75  {NULL, -1},
76};
77
78static int get_index(struct type arr[], char *name)
79{
80  int i;
81
82  for (i = 0; arr[i].name; i++)
83    if (!strcmp(arr[i].name, name)) break;
84  return arr[i].val;
85}
86
87static void resolve_host(char *host, struct sockaddr *sa)
88{
89  struct addrinfo *ai = xgetaddrinfo(host, NULL, AF_INET, SOCK_STREAM, 0, 0);
90
91  memcpy(sa, ai->ai_addr, ai->ai_addrlen);
92  freeaddrinfo(ai);
93}
94
95static void check_flags(int *i, char** argv)
96{
97  struct sockaddr sa;
98  int flag = *i, j;
99  struct flags {
100    char *name;
101    int or, flag;
102  } f[] = {
103    {"pub",  1 ,ATF_PUBL},
104    {"priv", 0 ,~ATF_PUBL},
105    {"trail", 1, ATF_USETRAILERS},
106    {"temp", 0, ~ATF_PERM},
107    {"dontpub",1, ATF_DONTPUB},
108  };
109
110  for (;*argv; argv++) {
111    for (j = 0;  j < ARRAY_LEN(f); j++) {
112      if (!strcmp(*argv, f[j].name)) {
113        (f[j].or) ?(flag |= f[j].flag):(flag &= f[j].flag);
114        break;
115      }
116    }
117    if (j > 4 && !strcmp(*argv, "netmask")) {
118      if (!*++argv) error_exit("NULL netmask");
119      if (strcmp(*argv, "255.255.255.255")) {
120        resolve_host(toys.optargs[0], &sa);
121        memcpy(&req.arp_netmask, &sa, sizeof(sa));
122        flag |= ATF_NETMASK;
123      } else argv++;
124    } else if (j > 4 && !strcmp(*argv, "dev")) {
125      if (!*++argv) error_exit("NULL dev");
126      TT.device = *argv;
127    } else if (j > 4) error_exit("invalid arg");
128  }
129  *i = flag;
130}
131
132static int set_entry(void)
133{
134  int flags = 0;
135
136  if (!toys.optargs[1]) error_exit("bad syntax");
137
138  if (!FLAG(D)) {
139    char *ptr = toys.optargs[1];
140    char *p = ptr, *hw_addr = req.arp_ha.sa_data;
141
142    while (*hw_addr && (p-ptr) < 6) {
143      int val, len;
144
145      if (*hw_addr == ':') hw_addr++;
146      if (!sscanf(hw_addr, "%2x%n", &val, &len)) break;
147      hw_addr += len;
148      *p++ = val;
149    }
150
151    if ((p-ptr) != 6 || *hw_addr)
152      error_exit("bad hw addr '%s'", req.arp_ha.sa_data);
153  } else {
154    struct ifreq ifre;
155
156    xstrncpy(ifre.ifr_name, toys.optargs[1], IFNAMSIZ);
157    xioctl(TT.sockfd, SIOCGIFHWADDR, &ifre);
158    if (FLAG(H) && ifre.ifr_hwaddr.sa_family != ARPHRD_ETHER)
159      error_exit("protocol type mismatch");
160    memcpy(&req.arp_ha, &(ifre.ifr_hwaddr), sizeof(req.arp_ha));
161  }
162
163  flags = ATF_PERM | ATF_COM;
164  if (toys.optargs[2]) check_flags(&flags, (toys.optargs+2));
165  req.arp_flags = flags;
166  xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev));
167  xioctl(TT.sockfd, SIOCSARP, &req);
168
169  if (FLAG(v)) xprintf("Entry set for %s\n", toys.optargs[0]);
170  return 0;
171}
172
173static int ip_to_host(struct sockaddr *sa, int flag)
174{
175  int status = 0;
176  char hbuf[NI_MAXHOST] = {0,}, sbuf[NI_MAXSERV] = {0,};
177  socklen_t len = sizeof(struct sockaddr_in6);
178
179  *toybuf = 0;
180  if (!(status = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf,
181          sizeof(sbuf), flag))) {
182    strcpy(toybuf, hbuf);
183    return 0;
184  }
185  return 1;
186}
187
188static int delete_entry(void)
189{
190  int flags = ATF_PERM;
191
192  if (toys.optargs[1]) check_flags(&flags, (toys.optargs+1));
193  req.arp_flags = flags;
194  xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev));
195  xioctl(TT.sockfd, SIOCDARP, &req);
196
197  if (FLAG(v)) xprintf("Delete entry for  %s\n", toys.optargs[0]);
198  return 0;
199}
200
201void arp_main(void)
202{
203  struct sockaddr sa;
204  char ip[16], hw_addr[30], mask[16], dev[16], *host_ip = NULL;
205  FILE *fp;
206  int h_type, type, flag, i, entries = 0, disp = 0;
207
208  TT.device = "";
209  memset(&sa, 0, sizeof(sa));
210  TT.sockfd = xsocket(AF_INET, SOCK_STREAM, 0);
211
212  if (FLAG(A) || FLAG(p)) {
213    if ((type = get_index(aftype,
214            (TT.af_type_A)?TT.af_type_A:TT.af_type_p)) != AF_INET)
215      error_exit((type != -1)?"only inet supported by kernel":"unknown family");
216  }
217
218  req.arp_ha.sa_family = ARPHRD_ETHER;
219  if (FLAG(H)) {
220    if ((type = get_index(hwtype, TT.hw_type)) != ARPHRD_ETHER)
221      error_exit((type != -1)?"h/w type not supported":"unknown h/w type");
222    req.arp_ha.sa_family = type;
223  }
224
225  if (FLAG(s) || FLAG(d)) {
226    if (!toys.optargs[0]) error_exit("-%c needs a host name", FLAG(d)?'d':'s');
227    resolve_host(toys.optargs[0], &sa);
228    memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
229
230    if (FLAG(s) && !set_entry()) return;
231    if (FLAG(d) && !delete_entry()) return;
232  }
233
234  // Show arp cache.
235
236  if (toys.optargs[0]) {
237    resolve_host(toys.optargs[0], &sa);
238    ip_to_host(&sa, NI_NUMERICHOST);
239    host_ip = xstrdup(toybuf);
240  }
241
242  fp = xfopen("/proc/net/arp", "r");
243  fgets(toybuf, sizeof(toybuf), fp); // Skip header.
244  while (fscanf(fp, "%15s 0x%x 0x%x %29s %15s %15s",
245                ip, &h_type, &flag, hw_addr, mask, dev) == 6) {
246    char *host_name = "?";
247
248    entries++;
249    if ((FLAG(H) && get_index(hwtype, TT.hw_type) != h_type) ||
250      (FLAG(i) && strcmp(TT.interface, dev)) ||
251      (toys.optargs[0] && strcmp(host_ip, ip))) {
252      continue;
253    }
254
255    resolve_host(ip, &sa);
256    if (FLAG(n)) ip_to_host(&sa, NI_NUMERICHOST);
257    else if (!ip_to_host(&sa, NI_NAMEREQD)) host_name = toybuf;
258
259    disp++;
260    printf("%s (%s) at" , host_name, ip);
261
262    for (i = 0; hwtype[i].name; i++)
263      if (hwtype[i].val & h_type) break;
264    if (!hwtype[i].name) error_exit("unknown h/w type");
265
266    if (!(flag & ATF_COM)) {
267      if ((flag & ATF_PUBL)) printf(" *");
268      else printf(" <incomplete>");
269    } else printf(" %s [%s]", hw_addr, hwtype[i].name);
270
271    if (flag & ATF_NETMASK) printf("netmask %s ", mask);
272
273    for (i = 0; flag_type[i].name; i++)
274      if (flag_type[i].val & flag) printf(" %s", flag_type[i].name);
275
276    printf(" on %s\n", dev);
277  }
278
279  if (FLAG(v))
280    xprintf("Entries: %d\tSkipped: %d\tFound: %d\n",
281        entries, entries - disp, disp);
282  if (toys.optargs[0] && !disp)
283    xprintf("%s (%s) -- no entry\n", toys.optargs[0], host_ip);
284
285  if (CFG_TOYBOX_FREE) {
286    free(host_ip);
287    fclose(fp);
288  }
289}
290