iproute.c

busybox-1.2.0,标准的Linux工具集[最新].对linux下软件的开发有着非常大的作用.

		struct rtmsg rtm;
	} req;
	struct sockaddr_nl nladdr;

	memset(&nladdr, 0, sizeof(nladdr));
	memset(&req, 0, sizeof(req));
	nladdr.nl_family = AF_NETLINK;

	req.nlh.nlmsg_len = sizeof(req);
	req.nlh.nlmsg_type = RTM_GETROUTE;
	req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_REQUEST;
	req.nlh.nlmsg_pid = 0;
	req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
	req.rtm.rtm_family = family;
	req.rtm.rtm_flags |= RTM_F_CLONED;

	return sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr));
}

static int iproute_flush_cache(void)
{
#define ROUTE_FLUSH_PATH "/proc/sys/net/ipv4/route/flush"

	int len;
	int flush_fd = open (ROUTE_FLUSH_PATH, O_WRONLY);
	char *buffer = "-1";

	if (flush_fd < 0) {
		fprintf (stderr, "Cannot open \"%s\"\n", ROUTE_FLUSH_PATH);
		return -1;
	}

	len = strlen (buffer);

	if ((write (flush_fd, (void *)buffer, len)) < len) {
		fprintf (stderr, "Cannot flush routing cache\n");
		return -1;
	}
	close(flush_fd);
	return 0;
}

static void iproute_reset_filter(void)
{
	memset(&filter, 0, sizeof(filter));
	filter.mdst.bitlen = -1;
	filter.msrc.bitlen = -1;
}

static int iproute_list_or_flush(int argc, char **argv, int flush)
{
	int do_ipv6 = preferred_family;
	struct rtnl_handle rth;
	char *id = NULL;
	char *od = NULL;

	iproute_reset_filter();
	filter.tb = RT_TABLE_MAIN;

	if (flush && argc <= 0) {
		bb_error_msg(bb_msg_requires_arg, "\"ip route flush\"");
		return -1;
	}

	while (argc > 0) {
		if (matches(*argv, "protocol") == 0) {
			uint32_t prot = 0;
			NEXT_ARG();
			filter.protocolmask = -1;
			if (rtnl_rtprot_a2n(&prot, *argv)) {
				if (strcmp(*argv, "all") != 0) {
					invarg(*argv, "protocol");
				}
				prot = 0;
				filter.protocolmask = 0;
			}
			filter.protocol = prot;
		} else if (strcmp(*argv, "dev") == 0 ||
			   strcmp(*argv, "oif") == 0) {
			NEXT_ARG();
			od = *argv;
		} else if (strcmp(*argv, "iif") == 0) {
			NEXT_ARG();
			id = *argv;
		} else if (matches(*argv, "from") == 0) {
			NEXT_ARG();
			if (matches(*argv, "root") == 0) {
				NEXT_ARG();
				get_prefix(&filter.rsrc, *argv, do_ipv6);
			} else if (matches(*argv, "match") == 0) {
				NEXT_ARG();
				get_prefix(&filter.msrc, *argv, do_ipv6);
			} else {
				if (matches(*argv, "exact") == 0) {
					NEXT_ARG();
				}
				get_prefix(&filter.msrc, *argv, do_ipv6);
				filter.rsrc = filter.msrc;
			}
		} else {
			if (matches(*argv, "to") == 0) {
				NEXT_ARG();
			}
			if (matches(*argv, "root") == 0) {
				NEXT_ARG();
				get_prefix(&filter.rdst, *argv, do_ipv6);
			} else if (matches(*argv, "match") == 0) {
				NEXT_ARG();
				get_prefix(&filter.mdst, *argv, do_ipv6);
			} else if (matches(*argv, "table") == 0) {
				NEXT_ARG();
				if (matches(*argv, "cache") == 0) {
					filter.tb = -1;
				} else if (matches(*argv, "main") != 0) {
					invarg(*argv, "table");
				}
			} else if (matches(*argv, "cache") == 0) {
				filter.tb = -1;
			} else {
				if (matches(*argv, "exact") == 0) {
					NEXT_ARG();
				}
				get_prefix(&filter.mdst, *argv, do_ipv6);
				filter.rdst = filter.mdst;
			}
		}
		argc--; argv++;
	}

	if (do_ipv6 == AF_UNSPEC && filter.tb) {
		do_ipv6 = AF_INET;
	}

	if (rtnl_open(&rth, 0) < 0) {
		exit(1);
	}

	ll_init_map(&rth);

	if (id || od)  {
		int idx;

		if (id) {
			if ((idx = ll_name_to_index(id)) == 0) {
				bb_error_msg("Cannot find device \"%s\"", id);
				return -1;
			}
			filter.iif = idx;
			filter.iifmask = -1;
		}
		if (od) {
			if ((idx = ll_name_to_index(od)) == 0) {
				bb_error_msg("Cannot find device \"%s\"", od);
			}
			filter.oif = idx;
			filter.oifmask = -1;
		}
	}

	if (flush) {
		char flushb[4096-512];

		if (filter.tb == -1) {
			if (do_ipv6 != AF_INET6)
				iproute_flush_cache();
			if (do_ipv6 == AF_INET)
				return 0;
		}

		filter.flushb = flushb;
		filter.flushp = 0;
		filter.flushe = sizeof(flushb);
		filter.rth = &rth;

		for (;;) {
			if (rtnl_wilddump_request(&rth, do_ipv6, RTM_GETROUTE) < 0) {
				perror("Cannot send dump request");
				return -1;
			}
			filter.flushed = 0;
			if (rtnl_dump_filter(&rth, print_route, stdout, NULL, NULL) < 0) {
				bb_error_msg("Flush terminated\n");
				return -1;
			}
			if (filter.flushed == 0) {
				fflush(stdout);
				return 0;
			}
			if (flush_update() < 0)
				exit(1);
		}
	}

	if (filter.tb != -1) {
		if (rtnl_wilddump_request(&rth, do_ipv6, RTM_GETROUTE) < 0) {
			bb_perror_msg_and_die("Cannot send dump request");
		}
	} else {
		if (rtnl_rtcache_request(&rth, do_ipv6) < 0) {
			bb_perror_msg_and_die("Cannot send dump request");
		}
	}

	if (rtnl_dump_filter(&rth, print_route, stdout, NULL, NULL) < 0) {
		bb_error_msg_and_die("Dump terminated");
	}

	exit(0);
}


static int iproute_get(int argc, char **argv)
{
	struct rtnl_handle rth;
	struct {
		struct nlmsghdr		n;
		struct rtmsg		r;
		char			buf[1024];
	} req;
	char  *idev = NULL;
	char  *odev = NULL;
	int connected = 0;
	int from_ok = 0;
	static const char * const options[] =
		{ "from", "iif", "oif", "dev", "notify", "connected", "to", 0 };

	memset(&req, 0, sizeof(req));

	iproute_reset_filter();

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
	req.n.nlmsg_flags = NLM_F_REQUEST;
	req.n.nlmsg_type = RTM_GETROUTE;
	req.r.rtm_family = preferred_family;
	req.r.rtm_table = 0;
	req.r.rtm_protocol = 0;
	req.r.rtm_scope = 0;
	req.r.rtm_type = 0;
	req.r.rtm_src_len = 0;
	req.r.rtm_dst_len = 0;
	req.r.rtm_tos = 0;

	while (argc > 0) {
		switch (compare_string_array(options, *argv)) {
			case 0: /* from */
			{
				inet_prefix addr;
				NEXT_ARG();
				from_ok = 1;
				get_prefix(&addr, *argv, req.r.rtm_family);
				if (req.r.rtm_family == AF_UNSPEC) {
					req.r.rtm_family = addr.family;
				}
				if (addr.bytelen) {
					addattr_l(&req.n, sizeof(req), RTA_SRC, &addr.data, addr.bytelen);
				}
				req.r.rtm_src_len = addr.bitlen;
				break;
			}
			case 1: /* iif */
				NEXT_ARG();
				idev = *argv;
				break;
			case 2: /* oif */
			case 3: /* dev */
				NEXT_ARG();
				odev = *argv;
				break;
			case 4: /* notify */
				req.r.rtm_flags |= RTM_F_NOTIFY;
				break;
			case 5: /* connected */
				connected = 1;
				break;
			case 6: /* to */
				NEXT_ARG();
			default:
			{
				inet_prefix addr;
				get_prefix(&addr, *argv, req.r.rtm_family);
				if (req.r.rtm_family == AF_UNSPEC) {
					req.r.rtm_family = addr.family;
				}
				if (addr.bytelen) {
					addattr_l(&req.n, sizeof(req), RTA_DST, &addr.data, addr.bytelen);
				}
				req.r.rtm_dst_len = addr.bitlen;
			}
			argc--; argv++;
		}
	}

	if (req.r.rtm_dst_len == 0) {
		bb_error_msg_and_die("need at least destination address");
	}

	if (rtnl_open(&rth, 0) < 0)
		exit(1);

	ll_init_map(&rth);

	if (idev || odev)  {
		int idx;

		if (idev) {
			if ((idx = ll_name_to_index(idev)) == 0) {
				bb_error_msg("Cannot find device \"%s\"", idev);
				return -1;
			}
			addattr32(&req.n, sizeof(req), RTA_IIF, idx);
		}
		if (odev) {
			if ((idx = ll_name_to_index(odev)) == 0) {
				bb_error_msg("Cannot find device \"%s\"", odev);
				return -1;
			}
			addattr32(&req.n, sizeof(req), RTA_OIF, idx);
		}
	}

	if (req.r.rtm_family == AF_UNSPEC) {
		req.r.rtm_family = AF_INET;
	}

	if (rtnl_talk(&rth, &req.n, 0, 0, &req.n, NULL, NULL) < 0) {
		exit(2);
	}

	if (connected && !from_ok) {
		struct rtmsg *r = NLMSG_DATA(&req.n);
		int len = req.n.nlmsg_len;
		struct rtattr * tb[RTA_MAX+1];

		if (print_route(NULL, &req.n, (void*)stdout) < 0) {
			bb_error_msg_and_die("An error :-)");
		}

		if (req.n.nlmsg_type != RTM_NEWROUTE) {
			bb_error_msg("Not a route?");
			return -1;
		}
		len -= NLMSG_LENGTH(sizeof(*r));
		if (len < 0) {
			bb_error_msg("Wrong len %d", len);
			return -1;
		}

		memset(tb, 0, sizeof(tb));
		parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);

		if (tb[RTA_PREFSRC]) {
			tb[RTA_PREFSRC]->rta_type = RTA_SRC;
			r->rtm_src_len = 8*RTA_PAYLOAD(tb[RTA_PREFSRC]);
		} else if (!tb[RTA_SRC]) {
			bb_error_msg("Failed to connect the route");
			return -1;
		}
		if (!odev && tb[RTA_OIF]) {
			tb[RTA_OIF]->rta_type = 0;
		}
		if (tb[RTA_GATEWAY]) {
			tb[RTA_GATEWAY]->rta_type = 0;
		}
		if (!idev && tb[RTA_IIF]) {
			tb[RTA_IIF]->rta_type = 0;
		}
		req.n.nlmsg_flags = NLM_F_REQUEST;
		req.n.nlmsg_type = RTM_GETROUTE;

		if (rtnl_talk(&rth, &req.n, 0, 0, &req.n, NULL, NULL) < 0) {
			exit(2);
		}
	}

	if (print_route(NULL, &req.n, (void*)stdout) < 0) {
		bb_error_msg_and_die("An error :-)");
	}

	exit(0);
}

int do_iproute(int argc, char **argv)
{
	static const char * const ip_route_commands[] =
		{ "add", "append", "change", "chg", "delete", "del", "get",
		"list", "show", "prepend", "replace", "test", "flush", 0 };
	int command_num = 7;
	unsigned int flags = 0;
	int cmd = RTM_NEWROUTE;

	if (*argv) {
		command_num = compare_string_array(ip_route_commands, *argv);
	}
	switch(command_num) {
		case 0: /* add*/
			flags = NLM_F_CREATE|NLM_F_EXCL;
			break;
		case 1: /* append */
			flags = NLM_F_CREATE|NLM_F_APPEND;
			break;
		case 2: /* change */
		case 3: /* chg */
			flags = NLM_F_REPLACE;
			break;
		case 4: /* delete */
		case 5: /* del */
			cmd = RTM_DELROUTE;
			break;
		case 6: /* get */
			return iproute_get(argc-1, argv+1);
		case 7: /* list */
		case 8: /* show */
			return iproute_list_or_flush(argc-1, argv+1, 0);
		case 9: /* prepend */
			flags = NLM_F_CREATE;
		case 10: /* replace */
			flags = NLM_F_CREATE|NLM_F_REPLACE;
		case 11: /* test */
			flags = NLM_F_EXCL;
		case 12: /* flush */
			return iproute_list_or_flush(argc-1, argv+1, 1);
		default:
			bb_error_msg_and_die("Unknown command %s", *argv);
	}

	return iproute_modify(cmd, flags, argc-1, argv+1);
}