2 This file is part of systemd.
4 Copyright (C) 2013 Intel Corporation. All rights reserved.
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
21 #include <sys/types.h>
22 #include <sys/socket.h>
24 #include <linux/if_packet.h>
25 #include <net/ethernet.h>
26 #include <net/if_arp.h>
29 #include <linux/filter.h>
31 #include "socket-util.h"
33 #include "dhcp-internal.h"
35 int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link,
36 uint32_t xid, struct ether_addr mac_addr) {
37 struct sock_filter filter[] = {
38 BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */
39 BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */
40 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
41 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
42 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */
43 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
44 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */
45 BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */
46 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
47 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
48 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
49 BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */
50 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
51 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
52 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */
53 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */
54 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
55 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */
56 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */
57 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
58 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */
59 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header type == ARPHRD_ETHER ? */
60 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
61 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- mac address length */
62 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHER_ADDR_LEN, 1, 0), /* address length == ETHER_ADDR_LEN ? */
63 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
64 BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */
65 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */
66 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
67 BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) &mac_addr))), /* A <- 4 bytes of client's MAC */
68 BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
69 BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */
70 BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
71 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
72 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
73 BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) &mac_addr) + 4)))), /* A <- remainder of client's MAC */
74 BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
75 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */
76 BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
77 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
78 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
79 BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */
80 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */
81 BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
82 BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
84 struct sock_fprog fprog = {
85 .len = ELEMENTSOF(filter),
88 _cleanup_close_ int s = -1;
94 s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
98 r = setsockopt (s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on));
102 r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
106 link->ll.sll_family = AF_PACKET;
107 link->ll.sll_protocol = htons(ETH_P_IP);
108 link->ll.sll_ifindex = index;
109 link->ll.sll_halen = ETH_ALEN;
110 memset(link->ll.sll_addr, 0xff, ETH_ALEN);
112 r = bind(s, &link->sa, sizeof(link->ll));
122 int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) {
123 union sockaddr_union src = {
124 .in.sin_family = AF_INET,
125 .in.sin_port = htobe16(port),
126 .in.sin_addr.s_addr = address,
128 _cleanup_close_ int s = -1;
129 int r, tos = IPTOS_CLASS_CS6;
131 s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
135 r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
139 if (address == INADDR_ANY) {
142 r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
146 r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
150 r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on));
155 r = bind(s, &src.sa, sizeof(src.in));
165 int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
166 const void *packet, size_t len) {
173 r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll));
180 int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
181 const void *packet, size_t len) {
182 union sockaddr_union dest = {
183 .in.sin_family = AF_INET,
184 .in.sin_port = htobe16(port),
185 .in.sin_addr.s_addr = address,
193 r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in));