/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2008-2011 Lennart Poettering systemd 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. systemd 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 systemd; 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 <stdlib.h> #include "ifconf.h" #define SEQ 4711 static int read_reply(int fd, struct address **list, unsigned *n_list) { ssize_t bytes; struct cmsghdr *cmsg; struct ucred *ucred; 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; struct iovec iov = { .iov_base = &resp, .iov_len = sizeof(resp), }; struct msghdr msg = { .msg_name = NULL, .msg_namelen = 0, .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cred_buffer, .msg_controllen = sizeof(cred_buffer), .msg_flags = 0, }; assert(fd >= 0); assert(list); bytes = recvmsg(fd, &msg, 0); if (bytes < 0) return -errno; cmsg = CMSG_FIRSTHDR(&msg); if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) return -EIO; ucred = (struct ucred*) CMSG_DATA(cmsg); if (ucred->uid != 0 || ucred->pid != 0) return 0; 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)) return -EIO; if (p->nlmsg_seq != SEQ) continue; if (p->nlmsg_type == NLMSG_DONE) return 1; if (p->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *nlmsgerr; nlmsgerr = NLMSG_DATA(p); return -nlmsgerr->error; } 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) return -ENOMEM; (*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)++; } return 0; } int ifconf_acquire_addresses(struct address **_list, unsigned *_n_list) { struct { struct nlmsghdr hdr; struct rtgenmsg gen; } req = { { .nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)), .nlmsg_type = RTM_GETADDR, .nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP|NLM_F_ACK, .nlmsg_seq = SEQ, .nlmsg_pid = 0, }, { .rtgen_family = AF_UNSPEC, } }; int r, on = 1; struct address *list = NULL; unsigned n_list = 0; int fd; 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; } if (send(fd, &req, req.hdr.nlmsg_len, 0) < 0) { r = -errno; goto finish; } while((r = read_reply(fd, &list, &n_list)) == 0) ; finish: close(fd); if (r < 0) { free(list); return r; } if (n_list) qsort(list, n_list, sizeof(struct address), address_compare); *_list = list; *_n_list = n_list; return 0; }