pimd: Multicast traceroute client and router

This commit is the implementation of weak multicast traceroute.
It consists of IGMP module dealing with mtrace type IGMP messages
and client program mtrace/mtracebis for initiating mtrace queries.

Signed-off-by: Mladen Sablic <mladen.sablic@gmail.com>

1 files changed, 700 insertions, 0 deletions

diff --git a/pimd/mtracebis_netlink.c b/pimd/mtracebis_netlink.c
new file mode 100644
index 000000000..42b80b218
--- /dev/null
+++ b/pimd/mtracebis_netlink.c
@@ -0,0 +1,700 @@
+/*
+ * libnetlink.c	RTnetlink service routines.
+ *
+ *		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.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ */
+
+#ifdef __linux__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <net/if_arp.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/uio.h>
+#include <assert.h>
+
+#include "mtracebis_netlink.h"
+
+int rcvbuf = 1024 * 1024;
+
+void rtnl_close(struct rtnl_handle *rth)
+{
+	if (rth->fd >= 0) {
+		close(rth->fd);
+		rth->fd = -1;
+	}
+}
+
+int rtnl_open_byproto(struct rtnl_handle *rth, unsigned subscriptions,
+		      int protocol)
+{
+	socklen_t addr_len;
+	int sndbuf = 32768;
+
+	memset(rth, 0, sizeof(*rth));
+
+	rth->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+	if (rth->fd < 0) {
+		perror("Cannot open netlink socket");
+		return -1;
+	}
+
+	if (setsockopt(rth->fd,SOL_SOCKET,SO_SNDBUF,&sndbuf,sizeof(sndbuf)) < 0) {
+		perror("SO_SNDBUF");
+		return -1;
+	}
+
+	if (setsockopt(rth->fd,SOL_SOCKET,SO_RCVBUF,&rcvbuf,sizeof(rcvbuf)) < 0) {
+		perror("SO_RCVBUF");
+		return -1;
+	}
+
+	memset(&rth->local, 0, sizeof(rth->local));
+	rth->local.nl_family = AF_NETLINK;
+	rth->local.nl_groups = subscriptions;
+
+	if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) {
+		perror("Cannot bind netlink socket");
+		return -1;
+	}
+	addr_len = sizeof(rth->local);
+	if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {
+		perror("Cannot getsockname");
+		return -1;
+	}
+	if (addr_len != sizeof(rth->local)) {
+		fprintf(stderr, "Wrong address length %d\n", addr_len);
+		return -1;
+	}
+	if (rth->local.nl_family != AF_NETLINK) {
+		fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family);
+		return -1;
+	}
+	rth->seq = time(NULL);
+	return 0;
+}
+
+int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
+{
+	return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
+}
+
+int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct rtgenmsg g;
+	} req;
+
+	memset(&req, 0, sizeof(req));
+	req.nlh.nlmsg_len = sizeof(req);
+	req.nlh.nlmsg_type = type;
+	req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
+	req.nlh.nlmsg_pid = 0;
+	req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
+	req.g.rtgen_family = family;
+
+	return send(rth->fd, (void*)&req, sizeof(req), 0);
+}
+
+int rtnl_send(struct rtnl_handle *rth, const char *buf, int len)
+{
+	return send(rth->fd, buf, len, 0);
+}
+
+int rtnl_send_check(struct rtnl_handle *rth, const char *buf, int len)
+{
+	struct nlmsghdr *h;
+	int status;
+	char resp[1024];
+
+	status = send(rth->fd, buf, len, 0);
+	if (status < 0)
+		return status;
+
+	/* Check for immediate errors */
+	status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
+	if (status < 0) {
+		if (errno == EAGAIN)
+			return 0;
+		return -1;
+	}
+
+	for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, (uint32_t)status);
+	     h = NLMSG_NEXT(h, status)) {
+		if (h->nlmsg_type == NLMSG_ERROR) {
+			struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
+			if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
+				fprintf(stderr, "ERROR truncated\n");
+			else
+				errno = -err->error;
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
+{
+	struct nlmsghdr nlh;
+	struct sockaddr_nl nladdr;
+	struct iovec iov[2] = {
+		{ .iov_base = &nlh, .iov_len = sizeof(nlh) },
+		{ .iov_base = req, .iov_len = len }
+	};
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = 	sizeof(nladdr),
+		.msg_iov = iov,
+		.msg_iovlen = 2,
+	};
+
+	memset(&nladdr, 0, sizeof(nladdr));
+	nladdr.nl_family = AF_NETLINK;
+
+	nlh.nlmsg_len = NLMSG_LENGTH(len);
+	nlh.nlmsg_type = type;
+	nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
+	nlh.nlmsg_pid = 0;
+	nlh.nlmsg_seq = rth->dump = ++rth->seq;
+
+	return sendmsg(rth->fd, &msg, 0);
+}
+
+int rtnl_dump_filter_l(struct rtnl_handle *rth,
+		       const struct rtnl_dump_filter_arg *arg)
+{
+	struct sockaddr_nl nladdr;
+	struct iovec iov;
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	char buf[16384];
+
+	iov.iov_base = buf;
+	while (1) {
+		int status;
+		const struct rtnl_dump_filter_arg *a;
+		int found_done = 0;
+		int msglen = 0;
+
+		iov.iov_len = sizeof(buf);
+		status = recvmsg(rth->fd, &msg, 0);
+
+		if (status < 0) {
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
+			fprintf(stderr, "netlink receive error %s (%d)\n",
+				strerror(errno), errno);
+			return -1;
+		}
+
+		if (status == 0) {
+			fprintf(stderr, "EOF on netlink\n");
+			return -1;
+		}
+
+		for (a = arg; a->filter; a++) {
+			struct nlmsghdr *h = (struct nlmsghdr*)buf;
+			msglen = status;
+
+			while (NLMSG_OK(h, (uint32_t)msglen)) {
+				int err;
+
+				if (nladdr.nl_pid != 0 ||
+				    h->nlmsg_pid != rth->local.nl_pid ||
+				    h->nlmsg_seq != rth->dump) {
+					if (a->junk) {
+						err = a->junk(&nladdr, h,
+							      a->arg2);
+						if (err < 0)
+							return err;
+					}
+					goto skip_it;
+				}
+
+				if (h->nlmsg_type == NLMSG_DONE) {
+					found_done = 1;
+					break; /* process next filter */
+				}
+				if (h->nlmsg_type == NLMSG_ERROR) {
+					struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
+					if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
+						fprintf(stderr,
+							"ERROR truncated\n");
+					} else {
+						errno = -err->error;
+						perror("RTNETLINK answers");
+					}
+					return -1;
+				}
+				err = a->filter(&nladdr, h, a->arg1);
+				if (err < 0)
+					return err;
+
+skip_it:
+				h = NLMSG_NEXT(h, msglen);
+			}
+		}
+
+		if (found_done)
+			return 0;
+
+		if (msg.msg_flags & MSG_TRUNC) {
+			fprintf(stderr, "Message truncated\n");
+			continue;
+		}
+		if (msglen) {
+			fprintf(stderr, "!!!Remnant of size %d\n", msglen);
+			exit(1);
+		}
+	}
+}
+
+int rtnl_dump_filter(struct rtnl_handle *rth,
+		     rtnl_filter_t filter,
+		     void *arg1,
+		     rtnl_filter_t junk,
+		     void *arg2)
+{
+	const struct rtnl_dump_filter_arg a[2] = {
+		{ .filter = filter, .arg1 = arg1, .junk = junk, .arg2 = arg2 },
+		{ .filter = NULL,   .arg1 = NULL, .junk = NULL, .arg2 = NULL }
+	};
+
+	return rtnl_dump_filter_l(rth, a);
+}
+
+int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
+	      unsigned groups, struct nlmsghdr *answer,
+	      rtnl_filter_t junk,
+	      void *jarg)
+{
+	int status;
+	unsigned seq;
+	struct nlmsghdr *h;
+	struct sockaddr_nl nladdr;
+	struct iovec iov = {
+		.iov_base = (void*) n,
+		.iov_len = n->nlmsg_len
+	};
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	char   buf[16384];
+
+	memset(&nladdr, 0, sizeof(nladdr));
+	nladdr.nl_family = AF_NETLINK;
+	nladdr.nl_pid = peer;
+	nladdr.nl_groups = groups;
+
+	n->nlmsg_seq = seq = ++rtnl->seq;
+
+	if (answer == NULL)
+		n->nlmsg_flags |= NLM_F_ACK;
+
+	status = sendmsg(rtnl->fd, &msg, 0);
+
+	if (status < 0) {
+		perror("Cannot talk to rtnetlink");
+		return -1;
+	}
+
+	memset(buf,0,sizeof(buf));
+
+	iov.iov_base = buf;
+
+	while (1) {
+		iov.iov_len = sizeof(buf);
+		status = recvmsg(rtnl->fd, &msg, 0);
+
+		if (status < 0) {
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
+			fprintf(stderr, "netlink receive error %s (%d)\n",
+				strerror(errno), errno);
+			return -1;
+		}
+		if (status == 0) {
+			fprintf(stderr, "EOF on netlink\n");
+			return -1;
+		}
+		if (msg.msg_namelen != sizeof(nladdr)) {
+			fprintf(stderr, "sender address length == %d\n", msg.msg_namelen);
+			exit(1);
+		}
+		for (h = (struct nlmsghdr*)buf; status >= (int)sizeof(*h); ) {
+			int err;
+			int len = h->nlmsg_len;
+			int l = len - sizeof(*h);
+
+			if (l<0 || len>status) {
+				if (msg.msg_flags & MSG_TRUNC) {
+					fprintf(stderr, "Truncated message\n");
+					return -1;
+				}
+				fprintf(stderr, "!!!malformed message: len=%d\n", len);
+				exit(1);
+			}
+
+			if ((int)nladdr.nl_pid != peer ||
+			    h->nlmsg_pid != rtnl->local.nl_pid ||
+			    h->nlmsg_seq != seq) {
+				if (junk) {
+					err = junk(&nladdr, h, jarg);
+					if (err < 0)
+						return err;
+				}
+				/* Don't forget to skip that message. */
+				status -= NLMSG_ALIGN(len);
+				h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
+				continue;
+			}
+
+			if (h->nlmsg_type == NLMSG_ERROR) {
+				struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
+				if (l < (int)sizeof(struct nlmsgerr)) {
+					fprintf(stderr, "ERROR truncated\n");
+				} else {
+					errno = -err->error;
+					if (errno == 0) {
+						if (answer)
+							memcpy(answer, h, h->nlmsg_len);
+						return 0;
+					}
+					perror("RTNETLINK answers");
+				}
+				return -1;
+			}
+			if (answer) {
+				memcpy(answer, h, h->nlmsg_len);
+				return 0;
+			}
+
+			fprintf(stderr, "Unexpected reply!!!\n");
+
+			status -= NLMSG_ALIGN(len);
+			h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
+		}
+		if (msg.msg_flags & MSG_TRUNC) {
+			fprintf(stderr, "Message truncated\n");
+			continue;
+		}
+		if (status) {
+			fprintf(stderr, "!!!Remnant of size %d\n", status);
+			exit(1);
+		}
+	}
+}
+
+int rtnl_listen(struct rtnl_handle *rtnl,
+		rtnl_filter_t handler,
+		void *jarg)
+{
+	int status;
+	struct nlmsghdr *h;
+	struct sockaddr_nl nladdr;
+	struct iovec iov;
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	char   buf[8192];
+
+	memset(&nladdr, 0, sizeof(nladdr));
+	nladdr.nl_family = AF_NETLINK;
+	nladdr.nl_pid = 0;
+	nladdr.nl_groups = 0;
+
+	iov.iov_base = buf;
+	while (1) {
+		iov.iov_len = sizeof(buf);
+		status = recvmsg(rtnl->fd, &msg, 0);
+
+		if (status < 0) {
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
+			fprintf(stderr, "netlink receive error %s (%d)\n",
+				strerror(errno), errno);
+			if (errno == ENOBUFS)
+				continue;
+			return -1;
+		}
+		if (status == 0) {
+			fprintf(stderr, "EOF on netlink\n");
+			return -1;
+		}
+		if (msg.msg_namelen != sizeof(nladdr)) {
+			fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen);
+			exit(1);
+		}
+		for (h =(struct nlmsghdr*)buf; status >= (int)sizeof(*h); ) {
+			int err;
+			int len = h->nlmsg_len;
+			int l = len - sizeof(*h);
+
+			if (l<0 || len>status) {
+				if (msg.msg_flags & MSG_TRUNC) {
+					fprintf(stderr, "Truncated message\n");
+					return -1;
+				}
+				fprintf(stderr, "!!!malformed message: len=%d\n", len);
+				exit(1);
+			}
+
+			err = handler(&nladdr, h, jarg);
+			if (err < 0)
+				return err;
+
+			status -= NLMSG_ALIGN(len);
+			h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
+		}
+		if (msg.msg_flags & MSG_TRUNC) {
+			fprintf(stderr, "Message truncated\n");
+			continue;
+		}
+		if (status) {
+			fprintf(stderr, "!!!Remnant of size %d\n", status);
+			exit(1);
+		}
+	}
+}
+
+int rtnl_from_file(FILE *rtnl, rtnl_filter_t handler,
+		   void *jarg)
+{
+	int status;
+	struct sockaddr_nl nladdr;
+	char   buf[8192];
+	struct nlmsghdr *h = (void*)buf;
+
+	memset(&nladdr, 0, sizeof(nladdr));
+	nladdr.nl_family = AF_NETLINK;
+	nladdr.nl_pid = 0;
+	nladdr.nl_groups = 0;
+
+	while (1) {
+		int err, len;
+		int l;
+
+		status = fread(&buf, 1, sizeof(*h), rtnl);
+
+		if (status < 0) {
+			if (errno == EINTR)
+				continue;
+			perror("rtnl_from_file: fread");
+			return -1;
+		}
+		if (status == 0)
+			return 0;
+
+		len = h->nlmsg_len;
+		l = len - sizeof(*h);
+
+		if (l<0 || len>(int)sizeof(buf)) {
+			fprintf(stderr, "!!!malformed message: len=%d @%lu\n",
+				len, ftell(rtnl));
+			return -1;
+		}
+
+		status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
+
+		if (status < 0) {
+			perror("rtnl_from_file: fread");
+			return -1;
+		}
+		if (status < l) {
+			fprintf(stderr, "rtnl-from_file: truncated message\n");
+			return -1;
+		}
+
+		err = handler(&nladdr, h, jarg);
+		if (err < 0)
+			return err;
+	}
+}
+
+int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
+{
+	int len = RTA_LENGTH(4);
+	struct rtattr *rta;
+	if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
+		fprintf(stderr,"addattr32: Error! max allowed bound %d exceeded\n",maxlen);
+		return -1;
+	}
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+	memcpy(RTA_DATA(rta), &data, 4);
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
+	return 0;
+}
+
+int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
+	      int alen)
+{
+	int len = RTA_LENGTH(alen);
+	struct rtattr *rta;
+
+	if ((int)(NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len)) > maxlen) {
+		fprintf(stderr, "addattr_l ERROR: message exceeded bound of %d\n",maxlen);
+		return -1;
+	}
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+
+	if (data)
+		memcpy(RTA_DATA(rta), data, alen);
+	else
+		assert(alen == 0);
+
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
+	return 0;
+}
+
+int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
+{
+	if ((int)(NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len)) > maxlen) {
+		fprintf(stderr, "addraw_l ERROR: message exceeded bound of %d\n",maxlen);
+		return -1;
+	}
+
+	memcpy(NLMSG_TAIL(n), data, len);
+	memset((uint8_t *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
+	return 0;
+}
+
+struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
+{
+	struct rtattr *nest = NLMSG_TAIL(n);
+
+	addattr_l(n, maxlen, type, NULL, 0);
+	return nest;
+}
+
+int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
+{
+	nest->rta_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)nest;
+	return n->nlmsg_len;
+}
+
+struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
+				   const void *data, int len)
+{
+	struct rtattr *start = NLMSG_TAIL(n);
+
+	addattr_l(n, maxlen, type, data, len);
+	addattr_nest(n, maxlen, type);
+	return start;
+}
+
+int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
+{
+	struct rtattr *nest = start + NLMSG_ALIGN(start->rta_len);
+
+	start->rta_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)start;
+	addattr_nest_end(n, nest);
+	return n->nlmsg_len;
+}
+
+int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
+{
+	int len = RTA_LENGTH(4);
+	struct rtattr *subrta;
+
+	if ((int)(RTA_ALIGN(rta->rta_len) + len) > maxlen) {
+		fprintf(stderr,"rta_addattr32: Error! max allowed bound %d exceeded\n",maxlen);
+		return -1;
+	}
+	subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
+	subrta->rta_type = type;
+	subrta->rta_len = len;
+	memcpy(RTA_DATA(subrta), &data, 4);
+	rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
+	return 0;
+}
+
+int rta_addattr_l(struct rtattr *rta, int maxlen, int type,
+		  const void *data, int alen)
+{
+	struct rtattr *subrta;
+	int len = RTA_LENGTH(alen);
+
+	if ((int)(RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len)) > maxlen) {
+		fprintf(stderr,"rta_addattr_l: Error! max allowed bound %d exceeded\n",maxlen);
+		return -1;
+	}
+	subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
+	subrta->rta_type = type;
+	subrta->rta_len = len;
+	memcpy(RTA_DATA(subrta), data, alen);
+	rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
+	return 0;
+}
+
+int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
+{
+	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+	while (RTA_OK(rta, len)) {
+		if ((rta->rta_type <= max) && (!tb[rta->rta_type]))
+			tb[rta->rta_type] = rta;
+		rta = RTA_NEXT(rta,len);
+	}
+	if (len)
+		fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);
+	return 0;
+}
+
+int parse_rtattr_byindex(struct rtattr *tb[], int max, struct rtattr *rta, int len)
+{
+	int i = 0;
+
+	memset(tb, 0, sizeof(struct rtattr *) * max);
+	while (RTA_OK(rta, len)) {
+		if (rta->rta_type <= max && i < max)
+			tb[i++] = rta;
+		rta = RTA_NEXT(rta,len);
+	}
+	if (len)
+		fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);
+	return i;
+}
+
+int __parse_rtattr_nested_compat(struct rtattr *tb[], int max, struct rtattr *rta,
+			         int len)
+{
+	if ((int)RTA_PAYLOAD(rta) < len)
+		return -1;
+	if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
+		rta = (struct rtattr *)(uint8_t *)RTA_DATA(rta)+RTA_ALIGN(len);
+		return parse_rtattr_nested(tb, max, rta);
+	}
+	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+	return 0;
+}
+
+#endif /* __linux__ */