/* * 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> * */ #include <sys/socket.h> #include <errno.h> #include <stdio.h> #include <string.h> #include <time.h> #include <unistd.h> #include <sys/uio.h> #include "libnetlink.h" #include "libbb.h" void rtnl_close(struct rtnl_handle *rth) { close(rth->fd); } int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions) { int addr_len; memset(rth, 0, sizeof(rth)); rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (rth->fd < 0) { bb_perror_msg("Cannot open netlink socket"); 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) { bb_perror_msg("Cannot bind netlink socket"); return -1; } addr_len = sizeof(rth->local); if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) { bb_perror_msg("Cannot getsockname"); return -1; } if (addr_len != sizeof(rth->local)) { bb_error_msg("Wrong address length %d", addr_len); return -1; } if (rth->local.nl_family != AF_NETLINK) { bb_error_msg("Wrong address family %d", rth->local.nl_family); return -1; } rth->seq = time(NULL); return 0; } int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) { struct { struct nlmsghdr nlh; struct rtgenmsg g; } req; struct sockaddr_nl nladdr; memset(&nladdr, 0, sizeof(nladdr)); nladdr.nl_family = AF_NETLINK; 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 sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr)); } int rtnl_send(struct rtnl_handle *rth, char *buf, int len) { struct sockaddr_nl nladdr; memset(&nladdr, 0, sizeof(nladdr)); nladdr.nl_family = AF_NETLINK; return sendto(rth->fd, buf, len, 0, (struct sockaddr*)&nladdr, sizeof(nladdr)); } 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] = { { &nlh, sizeof(nlh) }, { req, len } }; struct msghdr msg = { (void*)&nladdr, sizeof(nladdr), iov, 2, NULL, 0, 0 }; 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(struct rtnl_handle *rth, int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *), void *arg1, int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), void *arg2) { char buf[8192]; struct sockaddr_nl nladdr; struct iovec iov = { buf, sizeof(buf) }; while (1) { int status; struct nlmsghdr *h; struct msghdr msg = { (void*)&nladdr, sizeof(nladdr), &iov, 1, NULL, 0, 0 }; status = recvmsg(rth->fd, &msg, 0); if (status < 0) { if (errno == EINTR) continue; bb_perror_msg("OVERRUN"); continue; } if (status == 0) { bb_error_msg("EOF on netlink"); return -1; } if (msg.msg_namelen != sizeof(nladdr)) { bb_error_msg_and_die("sender address length == %d", msg.msg_namelen); } h = (struct nlmsghdr*)buf; while (NLMSG_OK(h, status)) { int err; if (nladdr.nl_pid != 0 || h->nlmsg_pid != rth->local.nl_pid || h->nlmsg_seq != rth->dump) { if (junk) { err = junk(&nladdr, h, arg2); if (err < 0) { return err; } } goto skip_it; } if (h->nlmsg_type == NLMSG_DONE) { return 0; } if (h->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h); if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) { bb_error_msg("ERROR truncated"); } else { errno = -l_err->error; bb_perror_msg("RTNETLINK answers"); } return -1; } err = filter(&nladdr, h, arg1); if (err < 0) { return err; } skip_it: h = NLMSG_NEXT(h, status); } if (msg.msg_flags & MSG_TRUNC) { bb_error_msg("Message truncated"); continue; } if (status) { bb_error_msg_and_die("!!!Remnant of size %d", status); } } } int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer, unsigned groups, struct nlmsghdr *answer, int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), void *jarg) { int status; unsigned seq; struct nlmsghdr *h; struct sockaddr_nl nladdr; struct iovec iov = { (void*)n, n->nlmsg_len }; char buf[8192]; struct msghdr msg = { (void*)&nladdr, sizeof(nladdr), &iov, 1, NULL, 0, 0 }; 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) { bb_perror_msg("Cannot talk to rtnetlink"); return -1; } iov.iov_base = buf; while (1) { iov.iov_len = sizeof(buf); status = recvmsg(rtnl->fd, &msg, 0); if (status < 0) { if (errno == EINTR) { continue; } bb_perror_msg("OVERRUN"); continue; } if (status == 0) { bb_error_msg("EOF on netlink"); return -1; } if (msg.msg_namelen != sizeof(nladdr)) { bb_error_msg_and_die("sender address length == %d", msg.msg_namelen); } for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) { int l_err; int len = h->nlmsg_len; int l = len - sizeof(*h); if (l<0 || len>status) { if (msg.msg_flags & MSG_TRUNC) { bb_error_msg("Truncated message"); return -1; } bb_error_msg_and_die("!!!malformed message: len=%d", len); } if (nladdr.nl_pid != peer || h->nlmsg_pid != rtnl->local.nl_pid || h->nlmsg_seq != seq) { if (junk) { l_err = junk(&nladdr, h, jarg); if (l_err < 0) { return l_err; } } continue; } if (h->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); if (l < sizeof(struct nlmsgerr)) { bb_error_msg("ERROR truncated"); } else { errno = -err->error; if (errno == 0) { if (answer) { memcpy(answer, h, h->nlmsg_len); } return 0; } bb_perror_msg("RTNETLINK answers"); } return -1; } if (answer) { memcpy(answer, h, h->nlmsg_len); return 0; } bb_error_msg("Unexpected reply!!!"); status -= NLMSG_ALIGN(len); h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len)); } if (msg.msg_flags & MSG_TRUNC) { bb_error_msg("Message truncated"); continue; } if (status) { bb_error_msg_and_die("!!!Remnant of size %d", status); } } } int rtnl_listen(struct rtnl_handle *rtnl, int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), void *jarg) { int status; struct nlmsghdr *h; struct sockaddr_nl nladdr; struct iovec iov; char buf[8192]; struct msghdr msg = { (void*)&nladdr, sizeof(nladdr), &iov, 1, NULL, 0, 0 }; 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) continue; bb_perror_msg("OVERRUN"); continue; } if (status == 0) { bb_error_msg("EOF on netlink"); return -1; } if (msg.msg_namelen != sizeof(nladdr)) { bb_error_msg_and_die("Sender address length == %d", msg.msg_namelen); } for (h = (struct nlmsghdr*)buf; status >= 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) { bb_error_msg("Truncated message"); return -1; } bb_error_msg_and_die("!!!malformed message: len=%d", len); } 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) { bb_error_msg("Message truncated"); continue; } if (status) { bb_error_msg_and_die("!!!Remnant of size %d", status); } } } int rtnl_from_file(FILE *rtnl, int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), 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, type; int l; status = fread(&buf, 1, sizeof(*h), rtnl); if (status < 0) { if (errno == EINTR) continue; bb_perror_msg("rtnl_from_file: fread"); return -1; } if (status == 0) return 0; len = h->nlmsg_len; type= h->nlmsg_type; l = len - sizeof(*h); if (l<0 || len>sizeof(buf)) { bb_error_msg("!!!malformed message: len=%d @%lu", len, ftell(rtnl)); return -1; } status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl); if (status < 0) { bb_perror_msg("rtnl_from_file: fread"); return -1; } if (status < l) { bb_error_msg("rtnl-from_file: truncated message"); 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 (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) return -1; rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len)); 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, void *data, int alen) { int len = RTA_LENGTH(alen); struct rtattr *rta; if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) return -1; rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len)); rta->rta_type = type; rta->rta_len = len; memcpy(RTA_DATA(rta), data, alen); n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len; return 0; } int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data) { int len = RTA_LENGTH(4); struct rtattr *subrta; if (RTA_ALIGN(rta->rta_len) + len > 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, void *data, int alen) { struct rtattr *subrta; int len = RTA_LENGTH(alen); if (RTA_ALIGN(rta->rta_len) + len > 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) + len; return 0; } int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len) { while (RTA_OK(rta, len)) { if (rta->rta_type <= max) { tb[rta->rta_type] = rta; } rta = RTA_NEXT(rta,len); } if (len) { bb_error_msg("!!!Deficit %d, rta_len=%d", len, rta->rta_len); } return 0; }