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- /* route.c - Display/edit network routing table.
- *
- * Copyright 2012 Ranjan Kumar <ranjankumar.bth@gmail.com>
- * Copyright 2013 Kyungwan Han <asura321@gmail.com>
- * Copyright 2020 Eric Molitor <eric@molitor.org>
- *
- * No Standard
- *
- * route add -net target 10.0.0.0 netmask 255.0.0.0 dev eth0
- * route del delete
- * delete net route, must match netmask, informative error message
- *
- * mod dyn reinstate metric netmask gw mss window irtt dev
- USE_ROUTE(NEWTOY(route, "?neA:", TOYFLAG_SBIN))
- config ROUTE
- bool "route"
- default n
- help
- usage: route [-ne] [-A [inet|inet6]] [add|del TARGET [OPTIONS]]
- Display, add or delete network routes in the "Forwarding Information Base",
- which send packets out a network interface to an address.
- -n Show numerical addresses (no DNS lookups)
- -e display netstat fields
- Assigning an address to an interface automatically creates an appropriate
- network route ("ifconfig eth0 10.0.2.15/8" does "route add 10.0.0.0/8 eth0"
- for you), although some devices (such as loopback) won't show it in the
- table. For machines more than one hop away, you need to specify a gateway
- (ala "route add default gw 10.0.2.2").
- The address "default" is a wildcard address (0.0.0.0/0) matching all
- packets without a more specific route.
- Available OPTIONS include:
- reject - blocking route (force match failure)
- dev NAME - force matching packets out this interface (ala "eth0")
- netmask - old way of saying things like ADDR/24
- gw ADDR - forward packets to gateway ADDR
- */
- #define FOR_route
- #include "toys.h"
- #define _LINUX_SYSINFO_H // workaround for musl bug
- #include <linux/rtnetlink.h>
- GLOBALS(
- char *A;
- )
- struct _arglist {
- char *arg;
- int action;
- };
- static struct _arglist arglist1[] = {
- { "add", 1 }, { "del", 2 },
- { "delete", 2 }, { NULL, 0 }
- };
- static struct _arglist arglist2[] = {
- { "-net", 1 }, { "-host", 2 },
- { NULL, 0 }
- };
- void xsend(int sockfd, void *buf, size_t len)
- {
- if (send(sockfd, buf, len, 0) != len) perror_exit("xsend");
- }
- int xrecv(int sockfd, void *buf, size_t len)
- {
- int msg_len = recv(sockfd, buf, len, 0);
- if (msg_len < 0) perror_exit("xrecv");
- return msg_len;
- }
- void addAttr(struct nlmsghdr *nl, int maxlen, void *attr, int type, int len)
- {
- struct rtattr *rt;
- int rtlen = RTA_LENGTH(len);
- if (NLMSG_ALIGN(nl->nlmsg_len) + rtlen > maxlen) perror_exit("addAttr");
- rt = (struct rtattr*)((char *)nl + NLMSG_ALIGN(nl->nlmsg_len));
- rt->rta_type = type;
- rt->rta_len = rtlen;
- memcpy(RTA_DATA(rt), attr, len);
- nl->nlmsg_len = NLMSG_ALIGN(nl->nlmsg_len) + rtlen;
- }
- static void get_hostname(sa_family_t f, void *a, char *dst, size_t len) {
- size_t a_len = (AF_INET6 == f) ? sizeof(struct in6_addr) : sizeof(struct in_addr);
- struct hostent *host = gethostbyaddr(a, a_len, f);
- if (host) xstrncpy(dst, host->h_name, len);
- }
- static void display_routes(sa_family_t f)
- {
- int fd, msg_hdr_len, route_protocol;
- struct {
- struct nlmsghdr nl;
- struct rtmsg rt;
- } req;
- struct nlmsghdr buf[8192 / sizeof(struct nlmsghdr)];
- struct nlmsghdr *msg_hdr_ptr;
- struct rtmsg *route_entry;
- struct rtattr *rteattr;
- fd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
- memset(&req, 0, sizeof(req));
- req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
- req.nl.nlmsg_type = RTM_GETROUTE;
- req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
- req.nl.nlmsg_pid = getpid();
- req.nl.nlmsg_seq = 1;
- req.rt.rtm_family = f;
- req.rt.rtm_table = RT_TABLE_MAIN;
- xsend(fd, &req, sizeof(req));
- if (f == AF_INET) {
- xprintf("Kernel IP routing table\n"
- "Destination Gateway Genmask Flags %s Iface\n",
- FLAG(e) ? " MSS Window irtt" : "Metric Ref Use");
- } else {
- xprintf("Kernel IPv6 routing table\n"
- "%-31s%-26s Flag Metric Ref Use If\n", "Destination", "Next Hop");
- }
- msg_hdr_len = xrecv(fd, buf, sizeof(buf));
- msg_hdr_ptr = buf;
- while (msg_hdr_ptr->nlmsg_type != NLMSG_DONE) {
- while (NLMSG_OK(msg_hdr_ptr, msg_hdr_len)) {
- route_entry = NLMSG_DATA(msg_hdr_ptr);
- route_protocol = route_entry->rtm_protocol;
- // Annoyingly NLM_F_MATCH is not yet implemented so even if we pass in
- // RT_TABLE_MAIN with RTM_GETROUTE it still returns everything so we
- // have to filter here.
- if (route_entry->rtm_table == RT_TABLE_MAIN) {
- int route_attribute_len;
- char dest[INET6_ADDRSTRLEN], gate[INET6_ADDRSTRLEN], netmask[32],
- flags[10] = "U", if_name[IF_NAMESIZE] = "-";
- unsigned priority = 0, mss = 0, win = 0, irtt = 0, ref = 0, use = 0,
- route_netmask, metric_len;
- struct in_addr netmask_addr;
- struct rtattr *metric;
- struct rta_cacheinfo *cache_info;
- if (f == AF_INET) {
- strcpy(dest, FLAG(n) ? "0.0.0.0" : "default");
- strcpy(gate, FLAG(n) ? "*" : "0.0.0.0");
- strcpy(netmask, "0.0.0.0");
- } else {
- strcpy(dest, "::");
- strcpy(gate, "::");
- }
- route_netmask = route_entry->rtm_dst_len;
- if (route_netmask == 0) netmask_addr.s_addr = ~((in_addr_t) -1);
- else netmask_addr.s_addr = htonl(~((1 << (32 - route_netmask)) - 1));
- inet_ntop(AF_INET, &netmask_addr, netmask, sizeof(netmask));
- rteattr = RTM_RTA(route_entry);
- route_attribute_len = RTM_PAYLOAD(msg_hdr_ptr);
- while (RTA_OK(rteattr, route_attribute_len)) {
- switch (rteattr->rta_type) {
- case RTA_DST:
- if (FLAG(n)) inet_ntop(f, RTA_DATA(rteattr), dest, sizeof(dest));
- else get_hostname(f, RTA_DATA(rteattr), dest, sizeof(dest));
- break;
- case RTA_GATEWAY:
- if (FLAG(n)) inet_ntop(f, RTA_DATA(rteattr), gate, sizeof(dest));
- else get_hostname(f, RTA_DATA(rteattr), gate, sizeof(dest));
- strcat(flags, "G");
- break;
- case RTA_PRIORITY:
- priority = *(unsigned *)RTA_DATA(rteattr);
- break;
- case RTA_OIF:
- if_indextoname(*(int *)RTA_DATA(rteattr), if_name);
- break;
- case RTA_METRICS:
- metric_len = RTA_PAYLOAD(rteattr);
- for (metric = RTA_DATA(rteattr); RTA_OK(metric, metric_len);
- metric = RTA_NEXT(metric, metric_len))
- if (metric->rta_type == RTAX_ADVMSS)
- mss = *(unsigned *)RTA_DATA(metric);
- else if (metric->rta_type == RTAX_WINDOW)
- win = *(unsigned *)RTA_DATA(metric);
- else if (metric->rta_type == RTAX_RTT)
- irtt = (*(unsigned *)RTA_DATA(metric))/8;
- break;
- case RTA_CACHEINFO:
- cache_info = RTA_DATA(rteattr);
- ref = cache_info->rta_clntref;
- use = cache_info->rta_used;
- break;
- }
- rteattr = RTA_NEXT(rteattr, route_attribute_len);
- }
- if (route_entry->rtm_type == RTN_UNREACHABLE) flags[0] = '!';
- if (route_netmask == 32) strcat(flags, "H");
- if (route_protocol == RTPROT_REDIRECT) strcat(flags, "D");
- if (f == AF_INET) {
- xprintf("%-15.15s %-15.15s %-16s%-6s", dest, gate, netmask, flags);
- if (FLAG(e)) xprintf("%5d %-5d %6d %s\n", mss, win, irtt, if_name);
- else xprintf("%-6d %-2d %7d %s\n", priority, ref, use, if_name);
- } else {
- char *dest_with_mask = xmprintf("%s/%u", dest, route_netmask);
- xprintf("%-30s %-26s %-4s %-6d %-4d %2d %-8s\n",
- dest_with_mask, gate, flags, priority, ref, use, if_name);
- free(dest_with_mask);
- }
- }
- msg_hdr_ptr = NLMSG_NEXT(msg_hdr_ptr, msg_hdr_len);
- }
- msg_hdr_len = xrecv(fd, buf, sizeof(buf));
- msg_hdr_ptr = buf;
- }
- xclose(fd);
- }
- // find parameter (add/del/net/host) in list, return appropriate action or 0.
- static int get_action(char ***argv, struct _arglist *list)
- {
- struct _arglist *alist;
- if (!**argv) return 0;
- for (alist = list; alist->arg; alist++) { //find the given parameter in list
- if (!strcmp(**argv, alist->arg)) {
- *argv += 1;
- return alist->action;
- }
- }
- return 0;
- }
- // add/del a route.
- static void setroute(sa_family_t f, char **argv)
- {
- char *tgtip;
- int sockfd, arg2_action;
- int action = get_action(&argv, arglist1); //verify the arg for add/del.
- struct nlmsghdr buf[8192 / sizeof(struct nlmsghdr)];
- struct nlmsghdr *nlMsg;
- struct rtmsg *rtMsg;
- if (!action || !*argv) help_exit("setroute");
- arg2_action = get_action(&argv, arglist2); //verify the arg for -net or -host
- if (!*argv) help_exit("setroute");
- tgtip = *argv++;
- sockfd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
- memset(buf, 0, sizeof(buf));
- nlMsg = (struct nlmsghdr *) buf;
- rtMsg = (struct rtmsg *) NLMSG_DATA(nlMsg);
- nlMsg->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
- //TODO(emolitor): Improve action and arg2_action handling
- if (action == 1) { // Add
- nlMsg->nlmsg_type = RTM_NEWROUTE;
- nlMsg->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
- } else { // Delete
- nlMsg->nlmsg_type = RTM_DELROUTE;
- nlMsg->nlmsg_flags = NLM_F_REQUEST;
- }
- nlMsg->nlmsg_pid = getpid();
- nlMsg->nlmsg_seq = 1;
- rtMsg->rtm_family = f;
- rtMsg->rtm_table = RT_TABLE_UNSPEC;
- rtMsg->rtm_type = RTN_UNICAST;
- rtMsg->rtm_protocol = RTPROT_UNSPEC;
- rtMsg->rtm_flags = RTM_F_NOTIFY;
- rtMsg->rtm_dst_len = rtMsg->rtm_src_len = (f == AF_INET) ? 32 : 128;
- if (arg2_action == 2) rtMsg->rtm_scope = RT_SCOPE_HOST;
- size_t addr_len = sizeof(struct in_addr);
- if (f == AF_INET6) addr_len = sizeof(struct in6_addr);
- unsigned char addr[sizeof(struct in6_addr)] = {0,};
- for (; *argv; argv++) {
- if (!strcmp(*argv, "mod")) continue;
- else if (!strcmp(*argv, "dyn")) continue;
- else if (!strcmp(*argv, "reinstate")) continue;
- else if (!strcmp(*argv, "reject")) rtMsg->rtm_type = RTN_UNREACHABLE;
- else {
- if (!argv[1]) show_help(stdout, 1);
- if (!strcmp(*argv, "metric")) {
- unsigned int priority = atolx_range(argv[1], 0, UINT_MAX);
- addAttr(nlMsg, sizeof(toybuf), &priority, RTA_PRIORITY, sizeof(unsigned int));
- } else if (!strcmp(*argv, "netmask")) {
- uint32_t netmask;
- char *ptr;
- uint32_t naddr[4] = {0,};
- uint64_t plen;
- netmask = (f == AF_INET6) ? 128 : 32; // set default netmask
- plen = strtoul(argv[1], &ptr, 0);
- if (!ptr || ptr == argv[1] || *ptr || !plen || plen > netmask) {
- if (!inet_pton(f, argv[1], &naddr)) error_exit("invalid netmask");
- if (f == AF_INET) {
- uint32_t mask = htonl(*naddr), host = ~mask;
- if (host & (host + 1)) error_exit("invalid netmask");
- for (plen = 0; mask; mask <<= 1) ++plen;
- if (plen > 32) error_exit("invalid netmask");
- }
- }
- netmask = plen;
- rtMsg->rtm_dst_len = netmask;
- } else if (!strcmp(*argv, "gw")) {
- if (!inet_pton(f, argv[1], &addr)) error_exit("invalid gw");
- addAttr(nlMsg, sizeof(toybuf), &addr, RTA_GATEWAY, addr_len);
- } else if (!strcmp(*argv, "mss")) {
- // TODO(emolitor): Add RTA_METRICS support
- //set the TCP Maximum Segment Size for connections over this route.
- //rt->rt_mtu = atolx_range(argv[1], 64, 65536);
- //rt->rt_flags |= RTF_MSS;
- } else if (!strcmp(*argv, "window")) {
- // TODO(emolitor): Add RTA_METRICS support
- //set the TCP window size for connections over this route to W bytes.
- //rt->rt_window = atolx_range(argv[1], 128, INT_MAX); //win low
- //rt->rt_flags |= RTF_WINDOW;
- } else if (!strcmp(*argv, "irtt")) {
- // TODO(emolitor): Add RTA_METRICS support
- //rt->rt_irtt = atolx_range(argv[1], 0, INT_MAX);
- //rt->rt_flags |= RTF_IRTT;
- } else if (!strcmp(*argv, "dev")) {
- unsigned int if_idx = if_nametoindex(argv[1]);
- if (!if_idx) perror_exit("dev");
- addAttr(nlMsg, sizeof(toybuf), &if_idx, RTA_OIF, sizeof(unsigned int));
- } else help_exit("no '%s'", *argv);
- argv++;
- }
- }
- if (strcmp(tgtip, "default") != 0) {
- char *prefix = strtok(0, "/");
- if (prefix) rtMsg->rtm_dst_len = strtoul(prefix, &prefix, 0);
- if (!inet_pton(f, strtok(tgtip, "/"), &addr)) error_exit("invalid target");
- addAttr(nlMsg, sizeof(toybuf), &addr, RTA_DST, addr_len);
- } else rtMsg->rtm_dst_len = 0;
- xsend(sockfd, nlMsg, nlMsg->nlmsg_len);
- xclose(sockfd);
- }
- void route_main(void)
- {
- if (!*toys.optargs) {
- if (!TT.A || !strcmp(TT.A, "inet")) display_routes(AF_INET);
- else if (!strcmp(TT.A, "inet6")) display_routes(AF_INET6);
- else show_help(stdout, 1);
- } else {
- if (!TT.A) {
- if (toys.optc>1 && strchr(toys.optargs[1], ':')) {
- xprintf("WARNING: Implicit IPV6 address using -Ainet6\n");
- TT.A = "inet6";
- } else TT.A = "inet";
- }
- if (!strcmp(TT.A, "inet")) setroute(AF_INET, toys.optargs);
- else setroute(AF_INET6, toys.optargs);
- }
- }
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