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 IF 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; //Global request structure
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
87
88void get_hw_add(char *hw_addr, char *ptr)
89{
90  char *p = ptr, *hw = hw_addr;
91
92  while (*hw_addr && (p-ptr) < 6) {
93    int val, len = 0;
94
95    if (*hw_addr == ':') hw_addr++;
96    sscanf(hw_addr, "%2x%n", &val, &len);
97    if (!len || len > 2) break;
98    hw_addr += len;
99    *p++ = val;
100  }
101
102  if ((p-ptr) != 6 || *hw_addr)
103    error_exit("bad hw addr '%s'", hw);
104}
105
106static void resolve_host(char *host, struct sockaddr *sa)
107{
108  struct addrinfo hints, *res = NULL;
109  int ret;
110
111  memset(&hints, 0, sizeof hints);
112  hints.ai_family = AF_INET;
113  hints.ai_socktype = SOCK_STREAM;
114  if ((ret = getaddrinfo(host, NULL, &hints, &res)))
115    perror_exit("%s", gai_strerror(ret));
116
117  memcpy(sa, res->ai_addr, res->ai_addrlen);
118  freeaddrinfo(res);
119}
120
121static void check_flags(int *i, char** argv)
122{
123  struct sockaddr sa;
124  int flag = *i, j;
125  struct flags {
126    char *name;
127    int or, flag;
128  } f[] = {
129    {"pub",  1 ,ATF_PUBL},
130    {"priv", 0 ,~ATF_PUBL},
131    {"trail", 1, ATF_USETRAILERS},
132    {"temp", 0, ~ATF_PERM},
133    {"dontpub",1, ATF_DONTPUB},
134  };
135
136  for (;*argv; argv++) {
137    for (j = 0;  j < ARRAY_LEN(f); j++) {
138      if (!strcmp(*argv, f[j].name)) {
139        (f[j].or) ?(flag |= f[j].flag):(flag &= f[j].flag);
140        break;
141      }
142    }
143    if (j > 4 && !strcmp(*argv, "netmask")) {
144      if (!*++argv) error_exit("NULL netmask");
145      if (strcmp(*argv, "255.255.255.255")) {
146        resolve_host(toys.optargs[0], &sa);
147        memcpy(&req.arp_netmask, &sa, sizeof(sa));
148        flag |= ATF_NETMASK;
149      } else argv++;
150    } else if (j > 4 && !strcmp(*argv, "dev")) {
151      if (!*++argv) error_exit("NULL dev");
152      TT.device = *argv;
153    } else if (j > 4) error_exit("invalid arg");
154  }
155  *i = flag;
156}
157
158static int set_entry(void)
159{
160  int flags = 0;
161
162  if (!toys.optargs[1]) error_exit("bad syntax");
163
164  if (!(toys.optflags & FLAG_D)) get_hw_add(toys.optargs[1], (char*)&req.arp_ha.sa_data);
165  else {
166    struct ifreq ifre;
167
168    xstrncpy(ifre.ifr_name, toys.optargs[1], IFNAMSIZ);
169    xioctl(TT.sockfd, SIOCGIFHWADDR, &ifre);
170    if ((toys.optflags & FLAG_H) && (ifre.ifr_hwaddr.sa_family != ARPHRD_ETHER))
171      error_exit("protocol type mismatch");
172    memcpy(&req.arp_ha, &(ifre.ifr_hwaddr), sizeof(req.arp_ha));
173  }
174
175  flags = ATF_PERM | ATF_COM;
176  if (toys.optargs[2]) check_flags(&flags, (toys.optargs+2));
177  req.arp_flags = flags;
178  xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev));
179  xioctl(TT.sockfd, SIOCSARP, &req);
180
181  if (toys.optflags & FLAG_v) xprintf("Entry set for %s\n", toys.optargs[0]);
182  return 0;
183}
184
185static int ip_to_host(struct sockaddr *sa, int flag)
186{
187  int status = 0;
188  char hbuf[NI_MAXHOST] = {0,}, sbuf[NI_MAXSERV] = {0,};
189  socklen_t len = sizeof(struct sockaddr_in6);
190
191  *toybuf = 0;
192  if (!(status = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf,
193          sizeof(sbuf), flag))) {
194    strcpy(toybuf, hbuf);
195    return 0;
196  }
197  return 1;
198}
199
200static int delete_entry(void)
201{
202  int flags;
203
204  flags = ATF_PERM;
205  if (toys.optargs[1]) check_flags(&flags, (toys.optargs+1));
206  req.arp_flags = flags;
207  xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev));
208  xioctl(TT.sockfd, SIOCDARP, &req);
209
210  if (toys.optflags & FLAG_v) xprintf("Delete entry for  %s\n", toys.optargs[0]);
211  return 0;
212}
213
214void arp_main(void)
215{
216  struct sockaddr sa;
217  char ip[128], hw_addr[128], mask[12], dev[128], *host_ip = NULL, *buf;
218  int h_type, type, flag, i, fd, entries = 0, disp = 0;
219
220  TT.device = "";
221  memset(&sa, 0, sizeof(sa));
222  memset(&req, 0, sizeof(req));
223  TT.sockfd = xsocket(AF_INET, SOCK_STREAM, 0);
224
225  if ((toys.optflags & FLAG_A) || (toys.optflags & FLAG_p)) {
226    if ((type = get_index(aftype,
227            (TT.af_type_A)?TT.af_type_A:TT.af_type_p)) != AF_INET)
228      error_exit((type != -1)?"only inet supported by kernel":"unknown family");
229  }
230
231  req.arp_ha.sa_family = ARPHRD_ETHER;
232  if (toys.optflags & FLAG_H) {
233    if ((type = get_index(hwtype, TT.hw_type)) != ARPHRD_ETHER)
234      error_exit((type != -1)?"h/w type not supported":"unknown h/w type");
235    req.arp_ha.sa_family = type;
236  }
237
238  if (((toys.optflags & FLAG_s) || toys.optflags & FLAG_d)) {
239    if (!toys.optargs[0]) error_exit("host name req");
240    resolve_host(toys.optargs[0], &sa);
241    memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
242  }
243
244  if ((toys.optflags & FLAG_s) && !set_entry()) return;
245  if ((toys.optflags & FLAG_d) && !delete_entry()) return;
246
247  //show arp chache
248  fd = xopen("/proc/net/arp", O_RDONLY);
249  buf = get_line(fd);
250  free(buf); //skip first line
251
252  if (toys.optargs[0]) {
253    resolve_host(toys.optargs[0], &sa);
254    ip_to_host(&sa, NI_NUMERICHOST);
255    host_ip = xstrdup(toybuf);
256  }
257
258  while ((buf = get_line(fd))) {
259    char *host_name = "?";
260
261    if ((sscanf(buf, "%s 0x%x 0x%x %s %s %s\n", ip,
262        &h_type, &flag, hw_addr, mask, dev )) != 6) break;
263    entries++;
264    if (((toys.optflags & FLAG_H) && (get_index(hwtype, TT.hw_type) != h_type))
265     || ((toys.optflags & FLAG_i) && strcmp(TT.interface, dev))
266     || (toys.optargs[0] && strcmp(host_ip, ip))) {
267      free(buf);
268      continue;
269    }
270
271    resolve_host(buf, &sa);
272    if (!(toys.optflags & FLAG_n)) {
273      if (!ip_to_host(&sa, NI_NAMEREQD)) host_name = toybuf;
274    } else ip_to_host(&sa, NI_NUMERICHOST);
275
276    disp++;
277    printf("%s (%s) at" , host_name, ip);
278
279    for (i = 0; hwtype[i].name; i++)
280      if (hwtype[i].val & h_type) break;
281    if (!hwtype[i].name) error_exit("unknown h/w type");
282
283    if (!(flag & ATF_COM)) {
284      if ((flag & ATF_PUBL)) printf(" *");
285      else printf(" <incomplete>");
286    } else printf(" %s [%s]", hw_addr, hwtype[i].name);
287
288    if (flag & ATF_NETMASK) printf("netmask %s ", mask);
289
290    for (i = 0; flag_type[i].name; i++)
291      if (flag_type[i].val & flag) printf(" %s", flag_type[i].name);
292
293    printf(" on %s\n", dev);
294    free(buf);
295  }
296
297  if (toys.optflags & FLAG_v)
298    xprintf("Entries: %d\tSkipped: %d\tFound: %d\n",
299        entries, entries - disp, disp);
300  if (!disp) xprintf("No Match found in %d entries\n", entries);
301
302  if (CFG_TOYBOX_FREE) {
303    free(host_ip);
304    free(buf);
305    xclose(fd);
306  }
307}
308