/*** This file is part of systemd. Copyright (C) 2014 Axis Communications AB. All rights reserved. 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 <linux/filter.h> #include "util.h" #include "ipv4ll-internal.h" int arp_network_send_raw_socket(int fd, const union sockaddr_union *link, const struct ether_arp *arp) { int r; assert(arp); assert(link); assert(fd >= 0); r = sendto(fd, arp, sizeof(struct ether_arp), 0, &link->sa, sizeof(link->ll)); if (r < 0) return -errno; return 0; } int arp_network_bind_raw_socket(int ifindex, union sockaddr_union *link) { static const struct sock_filter filter[] = { BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0), /* packet >= arp packet ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 0, 1), /* protocol == request ? */ BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), /* protocol == reply ? */ BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ }; struct sock_fprog fprog = { .len = ELEMENTSOF(filter), .filter = (struct sock_filter*) filter }; _cleanup_close_ int s = -1; int r; assert(ifindex > 0); assert(link); s = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); if (s < 0) return -errno; r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); if (r < 0) return -errno; link->ll.sll_family = AF_PACKET; link->ll.sll_protocol = htons(ETH_P_ARP); link->ll.sll_ifindex = ifindex; link->ll.sll_halen = ETH_ALEN; memset(link->ll.sll_addr, 0xff, ETH_ALEN); r = bind(s, &link->sa, sizeof(link->ll)); if (r < 0) return -errno; r = s; s = -1; return r; }