/*** This file is part of systemd. Copyright (C) 2013 Intel Corporation. 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 <errno.h> #include <sys/types.h> #include <sys/socket.h> #include <string.h> #include <linux/if_packet.h> #include <net/ethernet.h> #include <net/if_arp.h> #include <stdio.h> #include <unistd.h> #include <linux/filter.h> #include "socket-util.h" #include "dhcp-internal.h" int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, uint32_t xid) { 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(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ /* TODO: match ip.version */ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header type == ARPHRD_ETHER ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- mac address length */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHER_ADDR_LEN, 1, 0), /* address length == ETHER_ADDR_LEN ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ /* TODO: match chaddr */ BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ }; struct sock_fprog fprog = { .len = ELEMENTSOF(filter), .filter = filter }; _cleanup_close_ int s = -1; int r, on = 1; assert(index > 0); assert(link); s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); if (s < 0) return -errno; r = setsockopt (s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on)); if (r < 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_IP); link->ll.sll_ifindex = index; 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; } int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) { union sockaddr_union src = { .in.sin_family = AF_INET, .in.sin_port = htobe16(port), .in.sin_addr.s_addr = address, }; _cleanup_close_ int s = -1; int r, tos = IPTOS_CLASS_CS6; s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); if (s < 0) return -errno; r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); if (r < 0) return -errno; if (address == INADDR_ANY) { int on = 1; r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); if (r < 0) return -errno; r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on)); if (r < 0) return -errno; } r = bind(s, &src.sa, sizeof(src.in)); if (r < 0) return -errno; r = s; s = -1; return r; } int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, const void *packet, size_t len) { int r; assert(link); assert(packet); assert(len); r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll)); if (r < 0) return -errno; return 0; } int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port, const void *packet, size_t len) { union sockaddr_union dest = { .in.sin_family = AF_INET, .in.sin_port = htobe16(port), .in.sin_addr.s_addr = address, }; int r; assert(s >= 0); assert(packet); assert(len); r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)); if (r < 0) return -errno; return 0; }