/* vi: set sw=4 ts=4: */ /* * 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 <sys/uio.h> #include "libbb.h" #include "libnetlink.h" void rtnl_close(struct rtnl_handle *rth) { close(rth->fd); } int xrtnl_open(struct rtnl_handle *rth/*, unsigned subscriptions*/) { socklen_t addr_len; memset(rth, 0, sizeof(rth)); rth->fd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); memset(&rth->local, 0, sizeof(rth->local)); rth->local.nl_family = AF_NETLINK; /*rth->local.nl_groups = subscriptions;*/ xbind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)); addr_len = sizeof(rth->local); if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) bb_perror_msg_and_die("cannot getsockname"); if (addr_len != sizeof(rth->local)) bb_error_msg_and_die("wrong address length %d", addr_len); if (rth->local.nl_family != AF_NETLINK) bb_error_msg_and_die("wrong address family %d", rth->local.nl_family); rth->seq = time(NULL); return 0; } int xrtnl_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 xsendto(rth->fd, (void*)&req, sizeof(req), (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 xsendto(rth->fd, buf, len, (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); } static 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 xrtnl_dump_filter(struct rtnl_handle *rth, int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *), void *arg1) { int ret = rtnl_dump_filter(rth, filter, arg1/*, NULL, NULL*/); if (ret < 0) bb_error_msg_and_die("dump terminated"); return ret; } 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 addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t 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, uint32_t 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; }