/*** 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 <linux/if_infiniband.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" static int _bind_raw_socket(int ifindex, union sockaddr_union *link, uint32_t xid, const uint8_t *mac_addr, size_t mac_addr_len, const uint8_t *bcast_addr, const struct ether_addr *eth_mac, uint16_t arp_type, uint8_t dhcp_hlen) { 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 */ 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_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */ BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */ BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ 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, arp_type, 1, 0), /* header type == arp_type ? */ 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, dhcp_hlen, 1, 0), /* address length == dhcp_hlen ? */ 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 */ BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) eth_mac))), /* A <- 4 bytes of client's MAC */ BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */ BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */ BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */ BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ 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(ifindex > 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 = ifindex; link->ll.sll_hatype = htons(arp_type); link->ll.sll_halen = mac_addr_len; memcpy(link->ll.sll_addr, bcast_addr, mac_addr_len); r = bind(s, &link->sa, sizeof(link->ll)); if (r < 0) return -errno; r = s; s = -1; return r; } int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, uint32_t xid, const uint8_t *mac_addr, size_t mac_addr_len, uint16_t arp_type) { static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; /* Default broadcast address for IPoIB */ static const uint8_t ib_bcast[] = { 0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff }; struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } }; const uint8_t *bcast_addr = NULL; uint8_t dhcp_hlen = 0; assert_return(mac_addr_len > 0, -EINVAL); if (arp_type == ARPHRD_ETHER) { assert_return(mac_addr_len == ETH_ALEN, -EINVAL); memcpy(ð_mac, mac_addr, ETH_ALEN); bcast_addr = eth_bcast; dhcp_hlen = ETH_ALEN; } else if (arp_type == ARPHRD_INFINIBAND) { assert_return(mac_addr_len == INFINIBAND_ALEN, -EINVAL); bcast_addr = ib_bcast; } else return -EINVAL; return _bind_raw_socket(ifindex, link, xid, mac_addr, mac_addr_len, bcast_addr, ð_mac, arp_type, dhcp_hlen); } 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, on = 1, 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; r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); if (r < 0) return -errno; if (address == INADDR_ANY) { r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on)); if (r < 0) return -errno; r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)); if (r < 0) return -errno; } else { r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &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; }