/* arp.c - manipulate the system ARP cache * * Copyright 2014 Sandeep Sharma * Copyright 2014 Kyungwan Han * No Standard USE_ARP(NEWTOY(arp, "vi:nDsdap:A:H:[+Ap][!sd]", TOYFLAG_USR|TOYFLAG_BIN)) config ARP bool "arp" default n help Usage: arp [-vn] [-H HWTYPE] [-i IF] -a [HOSTNAME] [-v] [-i IF] -d HOSTNAME [pub] [-v] [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [temp] [-v] [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [netmask MASK] pub [-v] [-H HWTYPE] [-i IF] -Ds HOSTNAME IFACE [netmask MASK] pub Manipulate ARP cache -a Display (all) hosts -s Set new ARP entry -d Delete a specified entry -v Verbose -n Don't resolve names -i IF Network interface -D Read from given device -A,-p AF Protocol family -H HWTYPE Hardware address type */ #define FOR_arp #include "toys.h" #include GLOBALS( char *hw_type; char *af_type_A; char *af_type_p; char *interface; int sockfd; char *device; ) struct arpreq req; //Global request structure struct type { char *name; int val; }; struct type hwtype[] = { {"ether", ARPHRD_ETHER }, {"loop" ,ARPHRD_LOOPBACK}, {"ppp" ,ARPHRD_PPP}, {"infiniband" ,ARPHRD_INFINIBAND}, {NULL, -1}, }; struct type aftype[] = { {"inet", AF_INET }, {"inet6" ,AF_INET6}, {"unspec" ,AF_UNSPEC}, {NULL, -1}, }; struct type flag_type[] = { {"PERM", ATF_PERM }, {"PUB" ,ATF_PUBL}, {"DONTPUB" ,ATF_DONTPUB}, {"TRAIL" ,ATF_USETRAILERS}, {NULL, -1}, }; static int get_index(struct type arr[], char *name) { int i; for (i = 0; arr[i].name; i++) if (!strcmp(arr[i].name, name)) break; return arr[i].val; } static void resolve_host(char *host, struct sockaddr *sa) { struct addrinfo hints, *res = NULL; int ret; memset(&hints, 0, sizeof hints); hints.ai_family = AF_INET; hints.ai_socktype = SOCK_STREAM; if ((ret = getaddrinfo(host, NULL, &hints, &res))) perror_exit("%s", gai_strerror(ret)); memcpy(sa, res->ai_addr, res->ai_addrlen); freeaddrinfo(res); } static void check_flags(int *i, char** argv) { struct sockaddr sa; int flag = *i, j; struct flags { char *name; int or, flag; } f[] = { {"pub", 1 ,ATF_PUBL}, {"priv", 0 ,~ATF_PUBL}, {"trail", 1, ATF_USETRAILERS}, {"temp", 0, ~ATF_PERM}, {"dontpub",1, ATF_DONTPUB}, }; for (;*argv; argv++) { for (j = 0; j < ARRAY_LEN(f); j++) { if (!strcmp(*argv, f[j].name)) { (f[j].or) ?(flag |= f[j].flag):(flag &= f[j].flag); break; } } if (j > 4 && !strcmp(*argv, "netmask")) { if (!*++argv) error_exit("NULL netmask"); if (strcmp(*argv, "255.255.255.255")) { resolve_host(toys.optargs[0], &sa); memcpy(&req.arp_netmask, &sa, sizeof(sa)); flag |= ATF_NETMASK; } else argv++; } else if (j > 4 && !strcmp(*argv, "dev")) { if (!*++argv) error_exit("NULL dev"); TT.device = *argv; } else if (j > 4) error_exit("invalid arg"); } *i = flag; } static int set_entry(void) { int flags = 0; if (!toys.optargs[1]) error_exit("bad syntax"); if (!(toys.optflags & FLAG_D)) { char *ptr = toys.optargs[1]; char *p = ptr, *hw_addr = req.arp_ha.sa_data; while (*hw_addr && (p-ptr) < 6) { int val, len; if (*hw_addr == ':') hw_addr++; if (!sscanf(hw_addr, "%2x%n", &val, &len)) break; hw_addr += len; *p++ = val; } if ((p-ptr) != 6 || *hw_addr) error_exit("bad hw addr '%s'", req.arp_ha.sa_data); } else { struct ifreq ifre; xstrncpy(ifre.ifr_name, toys.optargs[1], IFNAMSIZ); xioctl(TT.sockfd, SIOCGIFHWADDR, &ifre); if ((toys.optflags & FLAG_H) && (ifre.ifr_hwaddr.sa_family != ARPHRD_ETHER)) error_exit("protocol type mismatch"); memcpy(&req.arp_ha, &(ifre.ifr_hwaddr), sizeof(req.arp_ha)); } flags = ATF_PERM | ATF_COM; if (toys.optargs[2]) check_flags(&flags, (toys.optargs+2)); req.arp_flags = flags; xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev)); xioctl(TT.sockfd, SIOCSARP, &req); if (toys.optflags & FLAG_v) xprintf("Entry set for %s\n", toys.optargs[0]); return 0; } static int ip_to_host(struct sockaddr *sa, int flag) { int status = 0; char hbuf[NI_MAXHOST] = {0,}, sbuf[NI_MAXSERV] = {0,}; socklen_t len = sizeof(struct sockaddr_in6); *toybuf = 0; if (!(status = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf), flag))) { strcpy(toybuf, hbuf); return 0; } return 1; } static int delete_entry(void) { int flags; flags = ATF_PERM; if (toys.optargs[1]) check_flags(&flags, (toys.optargs+1)); req.arp_flags = flags; xstrncpy(req.arp_dev, TT.device, sizeof(req.arp_dev)); xioctl(TT.sockfd, SIOCDARP, &req); if (toys.optflags & FLAG_v) xprintf("Delete entry for %s\n", toys.optargs[0]); return 0; } void arp_main(void) { struct sockaddr sa; char ip[128], hw_addr[128], mask[12], dev[128], *host_ip = NULL, *buf; int h_type, type, flag, i, fd, entries = 0, disp = 0; TT.device = ""; memset(&sa, 0, sizeof(sa)); memset(&req, 0, sizeof(req)); TT.sockfd = xsocket(AF_INET, SOCK_STREAM, 0); if ((toys.optflags & FLAG_A) || (toys.optflags & FLAG_p)) { if ((type = get_index(aftype, (TT.af_type_A)?TT.af_type_A:TT.af_type_p)) != AF_INET) error_exit((type != -1)?"only inet supported by kernel":"unknown family"); } req.arp_ha.sa_family = ARPHRD_ETHER; if (toys.optflags & FLAG_H) { if ((type = get_index(hwtype, TT.hw_type)) != ARPHRD_ETHER) error_exit((type != -1)?"h/w type not supported":"unknown h/w type"); req.arp_ha.sa_family = type; } if (((toys.optflags & FLAG_s) || toys.optflags & FLAG_d)) { if (!toys.optargs[0]) error_exit("host name req"); resolve_host(toys.optargs[0], &sa); memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); } if ((toys.optflags & FLAG_s) && !set_entry()) return; if ((toys.optflags & FLAG_d) && !delete_entry()) return; //show arp chache fd = xopenro("/proc/net/arp"); buf = get_line(fd); free(buf); //skip first line if (toys.optargs[0]) { resolve_host(toys.optargs[0], &sa); ip_to_host(&sa, NI_NUMERICHOST); host_ip = xstrdup(toybuf); } while ((buf = get_line(fd))) { char *host_name = "?"; if ((sscanf(buf, "%s 0x%x 0x%x %s %s %s\n", ip, &h_type, &flag, hw_addr, mask, dev )) != 6) break; entries++; if (((toys.optflags & FLAG_H) && (get_index(hwtype, TT.hw_type) != h_type)) || ((toys.optflags & FLAG_i) && strcmp(TT.interface, dev)) || (toys.optargs[0] && strcmp(host_ip, ip))) { free(buf); continue; } resolve_host(buf, &sa); if (!(toys.optflags & FLAG_n)) { if (!ip_to_host(&sa, NI_NAMEREQD)) host_name = toybuf; } else ip_to_host(&sa, NI_NUMERICHOST); disp++; printf("%s (%s) at" , host_name, ip); for (i = 0; hwtype[i].name; i++) if (hwtype[i].val & h_type) break; if (!hwtype[i].name) error_exit("unknown h/w type"); if (!(flag & ATF_COM)) { if ((flag & ATF_PUBL)) printf(" *"); else printf(" "); } else printf(" %s [%s]", hw_addr, hwtype[i].name); if (flag & ATF_NETMASK) printf("netmask %s ", mask); for (i = 0; flag_type[i].name; i++) if (flag_type[i].val & flag) printf(" %s", flag_type[i].name); printf(" on %s\n", dev); free(buf); } if (toys.optflags & FLAG_v) xprintf("Entries: %d\tSkipped: %d\tFound: %d\n", entries, entries - disp, disp); if (!disp) xprintf("No Match found in %d entries\n", entries); if (CFG_TOYBOX_FREE) { free(host_ip); free(buf); xclose(fd); } }