diff options
| -rw-r--r-- | networking/arp.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/networking/arp.c b/networking/arp.c new file mode 100644 index 0000000..10934c2 --- /dev/null +++ b/networking/arp.c @@ -0,0 +1,500 @@ +/* vi: set sw=4 ts=4: */ +/* + * arp.c - Manipulate the system ARP cache + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org> + * Busybox port: Paul van Gool <pvangool at mimotech.com> + * + * modified for getopt32 by Arne Bernin <arne [at] alamut.de> + */ + +#include "busybox.h" +#include "inet_common.h" + +#include <arpa/inet.h> +#include <net/if.h> +#include <net/if_arp.h> +#include <netinet/ether.h> +#include <netpacket/packet.h> + +#define DEBUG 0 + +#define DFLT_AF "inet" +#define DFLT_HW "ether" + +#define _PATH_PROCNET_ARP "/proc/net/arp" + +#define ARP_OPT_A (0x1) +#define ARP_OPT_p (0x2) +#define ARP_OPT_H (0x4) +#define ARP_OPT_t (0x8) +#define ARP_OPT_i (0x10) +#define ARP_OPT_a (0x20) +#define ARP_OPT_d (0x40) +#define ARP_OPT_n (0x80) /* do not resolve addresses */ +#define ARP_OPT_D (0x100) /* HW-address is devicename */ +#define ARP_OPT_s (0x200) +#define ARP_OPT_v (0x400 * DEBUG) /* debugging output flag */ + + +static const struct aftype *ap; /* current address family */ +static const struct hwtype *hw; /* current hardware type */ +static int sockfd; /* active socket descriptor */ +static smallint hw_set; /* flag if hw-type was set (-H) */ +static char *device = ""; /* current device */ + +static const char *const options[] = { + "pub", + "priv", + "temp", + "trail", + "dontpub", + "auto", + "dev", + "netmask", + NULL +}; + +/* Delete an entry from the ARP cache. */ +/* Called only from main, once */ +static int arp_del(char **args) +{ + char host[128]; + struct arpreq req; + struct sockaddr sa; + int flags = 0; + int err; + + memset(&req, 0, sizeof(req)); + + /* Resolve the host name. */ + safe_strncpy(host, *args, 128); + if (ap->input(0, host, &sa) < 0) { + bb_herror_msg_and_die("%s", host); + } + + /* If a host has more than one address, use the correct one! */ + memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); + + if (hw_set) + req.arp_ha.sa_family = hw->type; + + req.arp_flags = ATF_PERM; + args++; + while (*args != NULL) { + if (option_mask32 & ARP_OPT_v) + bb_error_msg("args=%s", *args); + + switch (index_in_str_array(options, *args)) { + case 0: // "pub" + flags |= 1; + args++; + break; + case 1: // "priv" + flags |= 2; + args++; + break; + case 2: // "temp" + req.arp_flags &= ~ATF_PERM; + args++; + break; + case 3: // "trail" + req.arp_flags |= ATF_USETRAILERS; + args++; + break; + case 4: // "dontpub" +#ifdef HAVE_ATF_DONTPUB + req.arp_flags |= ATF_DONTPUB; +#else + bb_error_msg("feature ATF_DONTPUB is not supported"); +#endif + args++; + break; + case 5: // "auto" +#ifdef HAVE_ATF_MAGIC + req.arp_flags |= ATF_MAGIC; +#else + bb_error_msg("feature ATF_MAGIC is not supported"); +#endif + args++; + break; + case 6: // "dev" + if (*++args == NULL) + bb_show_usage(); + device = *args; + args++; + break; + case 7: // "netmask" + if (*++args == NULL) + bb_show_usage(); + if (strcmp(*args, "255.255.255.255") != 0) { + safe_strncpy(host, *args, 128); + if (ap->input(0, host, &sa) < 0) { + bb_herror_msg("%s", host); + return -1; + } + memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); + req.arp_flags |= ATF_NETMASK; + } + args++; + break; + default: + bb_show_usage(); + break; + } + } + if (flags == 0) + flags = 3; + + strncpy(req.arp_dev, device, sizeof(req.arp_dev)); + + err = -1; + + /* Call the kernel. */ + if (flags & 2) { + if (option_mask32 & ARP_OPT_v) + bb_error_msg("SIOCDARP(nopub)"); + err = ioctl(sockfd, SIOCDARP, &req); + if (err < 0) { + if (errno == ENXIO) { + if (flags & 1) + goto nopub; + printf("No ARP entry for %s\n", host); + return -1; + } + bb_perror_msg_and_die("SIOCDARP(priv)"); + } + } + if ((flags & 1) && err) { + nopub: + req.arp_flags |= ATF_PUBL; + if (option_mask32 & ARP_OPT_v) + bb_error_msg("SIOCDARP(pub)"); + if (ioctl(sockfd, SIOCDARP, &req) < 0) { + if (errno == ENXIO) { + printf("No ARP entry for %s\n", host); + return -1; + } + bb_perror_msg_and_die("SIOCDARP(pub)"); + } + } + return 0; +} + +/* Get the hardware address to a specified interface name */ +static void +arp_getdevhw(char *ifname, struct sockaddr *sa, const struct hwtype *hwt) +{ + struct ifreq ifr; + const struct hwtype *xhw; + + strcpy(ifr.ifr_name, ifname); + if (ioctl(sockfd, SIOCGIFHWADDR, &ifr) < 0) { + bb_perror_msg_and_die("cant get HW-Address for '%s'", ifname); + } + if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) { + bb_error_msg_and_die("protocol type mismatch"); + } + memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr)); + + if (option_mask32 & ARP_OPT_v) { + xhw = get_hwntype(ifr.ifr_hwaddr.sa_family); + if (!xhw || !xhw->print) { + xhw = get_hwntype(-1); + } + bb_error_msg("device '%s' has HW address %s '%s'", + ifname, xhw->name, + xhw->print((char *) &ifr.ifr_hwaddr.sa_data)); + } +} + +/* Set an entry in the ARP cache. */ +/* Called only from main, once */ +static int arp_set(char **args) +{ + char host[128]; + struct arpreq req; + struct sockaddr sa; + int flags; + + memset(&req, 0, sizeof(req)); + + safe_strncpy(host, *args++, 128); + if (ap->input(0, host, &sa) < 0) { + bb_herror_msg_and_die("%s", host); + } + /* If a host has more than one address, use the correct one! */ + memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); + + /* Fetch the hardware address. */ + if (*args == NULL) { + bb_error_msg_and_die("need hardware address"); + } + if (option_mask32 & ARP_OPT_D) { + arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL); + } else { + if (hw->input(*args++, &req.arp_ha) < 0) { + bb_error_msg_and_die("invalid hardware address"); + } + } + + /* Check out any modifiers. */ + flags = ATF_PERM | ATF_COM; + while (*args != NULL) { + switch (index_in_str_array(options, *args)) { + case 0: // "pub" + flags |= ATF_PUBL; + args++; + break; + case 1: // "priv" + flags &= ~ATF_PUBL; + args++; + break; + case 2: // "temp" + flags &= ~ATF_PERM; + args++; + break; + case 3: // "trail" + flags |= ATF_USETRAILERS; + args++; + break; + case 4: // "dontpub" +#ifdef HAVE_ATF_DONTPUB + flags |= ATF_DONTPUB; +#else + bb_error_msg("feature ATF_DONTPUB is not supported"); +#endif + args++; + break; + case 5: // "auto" +#ifdef HAVE_ATF_MAGIC + flags |= ATF_MAGIC; +#else + bb_error_msg("feature ATF_MAGIC is not supported"); +#endif + args++; + break; + case 6: // "dev" + if (*++args == NULL) + bb_show_usage(); + device = *args; + args++; + break; + case 7: // "netmask" + if (*++args == NULL) + bb_show_usage(); + if (strcmp(*args, "255.255.255.255") != 0) { + safe_strncpy(host, *args++, 128); + if (ap->input(0, host, &sa) < 0) { + bb_herror_msg_and_die("%s", host); + } + memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); + flags |= ATF_NETMASK; + } + args++; + break; + default: + bb_show_usage(); + break; + } + } + + /* Fill in the remainder of the request. */ + req.arp_flags = flags; + + strncpy(req.arp_dev, device, sizeof(req.arp_dev)); + + /* Call the kernel. */ + if (option_mask32 & ARP_OPT_v) + bb_error_msg("SIOCSARP()"); + if (ioctl(sockfd, SIOCSARP, &req) < 0) { + bb_perror_msg_and_die("SIOCSARP"); + } + return 0; +} + + +/* Print the contents of an ARP request block. */ +static void +arp_disp(char *name, char *ip, int type, int arp_flags, + char *hwa, char *mask, char *dev) +{ + const struct hwtype *xhw; + + xhw = get_hwntype(type); + if (xhw == NULL) + xhw = get_hwtype(DFLT_HW); + + printf("%s (%s) at ", name, ip); + + if (!(arp_flags & ATF_COM)) { + if (arp_flags & ATF_PUBL) + printf("* "); + else + printf("<incomplete> "); + } else { + printf("%s [%s] ", hwa, xhw->name); + } + + if (arp_flags & ATF_NETMASK) + printf("netmask %s ", mask); + + if (arp_flags & ATF_PERM) + printf("PERM "); + if (arp_flags & ATF_PUBL) + printf("PUP "); +#ifdef HAVE_ATF_MAGIC + if (arp_flags & ATF_MAGIC) + printf("AUTO "); +#endif +#ifdef HAVE_ATF_DONTPUB + if (arp_flags & ATF_DONTPUB) + printf("DONTPUB "); +#endif + if (arp_flags & ATF_USETRAILERS) + printf("TRAIL "); + + printf("on %s\n", dev); +} + +/* Display the contents of the ARP cache in the kernel. */ +/* Called only from main, once */ +static int arp_show(char *name) +{ + char host[100]; + struct sockaddr sa; + char ip[100]; + char hwa[100]; + char mask[100]; + char line[200]; + char dev[100]; + int type, flags; + FILE *fp; + char *hostname; + int num, entries = 0, shown = 0; + + host[0] = '\0'; + + if (name != NULL) { + /* Resolve the host name. */ + safe_strncpy(host, name, (sizeof host)); + if (ap->input(0, host, &sa) < 0) { + bb_herror_msg_and_die("%s", host); + } + safe_strncpy(host, ap->sprint(&sa, 1), sizeof(host)); + } + /* Open the PROCps kernel table. */ + fp = xfopen(_PATH_PROCNET_ARP, "r"); + /* Bypass header -- read until newline */ + if (fgets(line, sizeof(line), fp) != (char *) NULL) { + mask[0] = '-'; mask[1] = '\0'; + dev[0] = '-'; dev[1] = '\0'; + /* Read the ARP cache entries. */ + for (; fgets(line, sizeof(line), fp);) { + num = sscanf(line, "%s 0x%x 0x%x %100s %100s %100s\n", + ip, &type, &flags, hwa, mask, dev); + if (num < 4) + break; + + entries++; + /* if the user specified hw-type differs, skip it */ + if (hw_set && (type != hw->type)) + continue; + + /* if the user specified address differs, skip it */ + if (host[0] && strcmp(ip, host) != 0) + continue; + + /* if the user specified device differs, skip it */ + if (device && strcmp(dev, device) != 0) + continue; + + shown++; + /* This IS ugly but it works -be */ + if (option_mask32 & ARP_OPT_n) + hostname = "?"; + else { + if (ap->input(0, ip, &sa) < 0) + hostname = ip; + else + hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000); + if (strcmp(hostname, ip) == 0) + hostname = "?"; + } + + arp_disp(hostname, ip, type, flags, hwa, mask, dev); + } + } + if (option_mask32 & ARP_OPT_v) + printf("Entries: %d\tSkipped: %d\tFound: %d\n", + entries, entries - shown, shown); + + if (!shown) { + if (hw_set || host[0] || device) + printf("No match found in %d entries\n", entries); + } + + fclose(fp); + + return 0; +} + +int arp_main(int argc, char **argv) +{ + char *hw_type; + char *protocol; + + /* Initialize variables... */ + ap = get_aftype(DFLT_AF); + if (!ap) + bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family"); + + getopt32(argc, argv, "A:p:H:t:i:adnDsv", &protocol, &protocol, + &hw_type, &hw_type, &device); + argv += optind; + if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { + ap = get_aftype(protocol); + if (ap == NULL) + bb_error_msg_and_die("%s: unknown %s", protocol, "address family"); + } + if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { + hw = get_hwtype(hw_type); + if (hw == NULL) + bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type"); + hw_set = 1; + } + //if (option_mask32 & ARP_OPT_i)... -i + + if (ap->af != AF_INET) { + bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name); + } + + /* If no hw type specified get default */ + if (!hw) { + hw = get_hwtype(DFLT_HW); + if (!hw) + bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type"); + } + + if (hw->alen <= 0) { + bb_error_msg_and_die("%s: %s without ARP support", + hw->name, "hardware type"); + } + sockfd = xsocket(AF_INET, SOCK_DGRAM, 0); + + /* Now see what we have to do here... */ + if (option_mask32 & (ARP_OPT_d|ARP_OPT_s)) { + if (argv[0] == NULL) + bb_error_msg_and_die("need host name"); + if (option_mask32 & ARP_OPT_s) + return arp_set(argv); + return arp_del(argv); + } + //if (option_mask32 & ARP_OPT_a) - default + return arp_show(argv[0]); +} |