/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of nss-myhostname. Copyright 2008-2011 Lennart Poettering nss-myhostname is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. nss-myhostname is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with nss-myhostname; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/socket.h> #include <sys/un.h> #include <asm/types.h> #include <inttypes.h> #include <linux/netlink.h> #include <linux/rtnetlink.h> #include <string.h> #include <assert.h> #include <errno.h> #include <limits.h> #include <arpa/inet.h> #include <unistd.h> #include <inttypes.h> #include <stdlib.h> #include "ifconf.h" int ifconf_acquire_addresses(struct address **_list, unsigned *_n_list) { struct { struct nlmsghdr hdr; struct rtgenmsg gen; } req; struct rtgenmsg *gen; int fd, r, on = 1; uint32_t seq = 4711; struct address *list = NULL; unsigned n_list = 0; fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); if (fd < 0) return -errno; if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) { r = -errno; goto finish; } memset(&req, 0, sizeof(req)); req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)); req.hdr.nlmsg_type = RTM_GETADDR; req.hdr.nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP|NLM_F_ACK; req.hdr.nlmsg_seq = seq; req.hdr.nlmsg_pid = 0; gen = NLMSG_DATA(&req.hdr); gen->rtgen_family = AF_UNSPEC; if (send(fd, &req, req.hdr.nlmsg_len, 0) < 0) { r = -errno; goto finish; } for (;;) { ssize_t bytes; struct msghdr msg; struct cmsghdr *cmsg; struct ucred *ucred; struct iovec iov; struct nlmsghdr *p; uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))]; struct { struct nlmsghdr hdr; struct ifaddrmsg ifaddrmsg; uint8_t payload[16*1024]; } resp; memset(&iov, 0, sizeof(iov)); iov.iov_base = &resp; iov.iov_len = sizeof(resp); memset(&msg, 0, sizeof(msg)); msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_control = cred_buffer; msg.msg_controllen = sizeof(cred_buffer); msg.msg_flags = 0; bytes = recvmsg(fd, &msg, 0); if (bytes < 0) { r = -errno; goto finish; } cmsg = CMSG_FIRSTHDR(&msg); if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) { r = -EIO; goto finish; } ucred = (struct ucred*) CMSG_DATA(cmsg); if (ucred->uid != 0 || ucred->pid != 0) continue; for (p = &resp.hdr; bytes > 0; p = NLMSG_NEXT(p, bytes)) { struct ifaddrmsg *ifaddrmsg; struct rtattr *a; size_t l; void *local = NULL, *address = NULL; if (!NLMSG_OK(p, (size_t) bytes)) { r = -EIO; goto finish; } if (p->nlmsg_seq != seq) continue; if (p->nlmsg_type == NLMSG_DONE) { r = 0; goto finish; } if (p->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *nlmsgerr; nlmsgerr = NLMSG_DATA(p); r = -nlmsgerr->error; goto finish; } if (p->nlmsg_type != RTM_NEWADDR) continue; ifaddrmsg = NLMSG_DATA(p); if (ifaddrmsg->ifa_family != AF_INET && ifaddrmsg->ifa_family != AF_INET6) continue; if (ifaddrmsg->ifa_scope == RT_SCOPE_HOST || ifaddrmsg->ifa_scope == RT_SCOPE_NOWHERE) continue; if (ifaddrmsg->ifa_flags & IFA_F_DEPRECATED) continue; l = NLMSG_PAYLOAD(p, sizeof(struct ifaddrmsg)); a = IFA_RTA(ifaddrmsg); while (RTA_OK(a, l)) { if (a->rta_type == IFA_ADDRESS) address = RTA_DATA(a); else if (a->rta_type == IFA_LOCAL) local = RTA_DATA(a); a = RTA_NEXT(a, l); } if (local) address = local; if (!address) continue; list = realloc(list, (n_list+1) * sizeof(struct address)); if (!list) { r = -ENOMEM; goto finish; } list[n_list].family = ifaddrmsg->ifa_family; list[n_list].scope = ifaddrmsg->ifa_scope; memcpy(list[n_list].address, address, ifaddrmsg->ifa_family == AF_INET ? 4 : 16); list[n_list].ifindex = ifaddrmsg->ifa_index; n_list++; } } finish: close(fd); if (r < 0) free(list); else { qsort(list, n_list, sizeof(struct address), address_compare); *_list = list; *_n_list = n_list; } return r; }