Line data Source code
1 : /***
2 : This file is part of systemd.
3 :
4 : Copyright (C) 2013 Intel Corporation. All rights reserved.
5 :
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.
10 :
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.
15 :
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/>.
18 : ***/
19 :
20 : #include <errno.h>
21 : #include <sys/socket.h>
22 : #include <string.h>
23 : #include <linux/if_packet.h>
24 : #include <linux/if_infiniband.h>
25 : #include <net/ethernet.h>
26 : #include <net/if_arp.h>
27 : #include <stdio.h>
28 : #include <linux/filter.h>
29 :
30 : #include "socket-util.h"
31 :
32 : #include "dhcp-internal.h"
33 :
34 0 : static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
35 : uint32_t xid, const uint8_t *mac_addr,
36 : size_t mac_addr_len,
37 : const uint8_t *bcast_addr,
38 : const struct ether_addr *eth_mac,
39 : uint16_t arp_type, uint8_t dhcp_hlen) {
40 0 : struct sock_filter filter[] = {
41 : BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */
42 : BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */
43 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
44 : BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
45 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */
46 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
47 : BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */
48 : BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */
49 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
50 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
51 : BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
52 : BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */
53 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
54 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
55 : BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */
56 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */
57 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
58 : BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */
59 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */
60 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
61 : BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */
62 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, arp_type, 1, 0), /* header type == arp_type ? */
63 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
64 : BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- MAC address length */
65 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, dhcp_hlen, 1, 0), /* address length == dhcp_hlen ? */
66 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
67 : BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */
68 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */
69 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
70 0 : BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) eth_mac))), /* A <- 4 bytes of client's MAC */
71 : BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
72 : BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */
73 : BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
74 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
75 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
76 0 : BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */
77 : BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
78 : BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */
79 : BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
80 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
81 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
82 : BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */
83 : BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */
84 : BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
85 : BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
86 : };
87 0 : struct sock_fprog fprog = {
88 : .len = ELEMENTSOF(filter),
89 : .filter = filter
90 : };
91 0 : _cleanup_close_ int s = -1;
92 0 : int r, on = 1;
93 :
94 0 : assert(ifindex > 0);
95 0 : assert(link);
96 :
97 0 : s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
98 0 : if (s < 0)
99 0 : return -errno;
100 :
101 0 : r = setsockopt(s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on));
102 0 : if (r < 0)
103 0 : return -errno;
104 :
105 0 : r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
106 0 : if (r < 0)
107 0 : return -errno;
108 :
109 0 : link->ll.sll_family = AF_PACKET;
110 0 : link->ll.sll_protocol = htons(ETH_P_IP);
111 0 : link->ll.sll_ifindex = ifindex;
112 0 : link->ll.sll_hatype = htons(arp_type);
113 0 : link->ll.sll_halen = mac_addr_len;
114 0 : memcpy(link->ll.sll_addr, bcast_addr, mac_addr_len);
115 :
116 0 : r = bind(s, &link->sa, sizeof(link->ll));
117 0 : if (r < 0)
118 0 : return -errno;
119 :
120 0 : r = s;
121 0 : s = -1;
122 :
123 0 : return r;
124 : }
125 :
126 0 : int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link,
127 : uint32_t xid, const uint8_t *mac_addr,
128 : size_t mac_addr_len, uint16_t arp_type) {
129 : static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
130 : /* Default broadcast address for IPoIB */
131 : static const uint8_t ib_bcast[] = {
132 : 0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b,
133 : 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
134 : 0xff, 0xff, 0xff, 0xff
135 : };
136 0 : struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } };
137 0 : const uint8_t *bcast_addr = NULL;
138 0 : uint8_t dhcp_hlen = 0;
139 :
140 0 : assert_return(mac_addr_len > 0, -EINVAL);
141 :
142 0 : if (arp_type == ARPHRD_ETHER) {
143 0 : assert_return(mac_addr_len == ETH_ALEN, -EINVAL);
144 0 : memcpy(ð_mac, mac_addr, ETH_ALEN);
145 0 : bcast_addr = eth_bcast;
146 0 : dhcp_hlen = ETH_ALEN;
147 0 : } else if (arp_type == ARPHRD_INFINIBAND) {
148 0 : assert_return(mac_addr_len == INFINIBAND_ALEN, -EINVAL);
149 0 : bcast_addr = ib_bcast;
150 : } else
151 0 : return -EINVAL;
152 :
153 0 : return _bind_raw_socket(ifindex, link, xid, mac_addr, mac_addr_len,
154 : bcast_addr, ð_mac, arp_type, dhcp_hlen);
155 : }
156 :
157 0 : int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) {
158 0 : union sockaddr_union src = {
159 : .in.sin_family = AF_INET,
160 0 : .in.sin_port = htobe16(port),
161 : .in.sin_addr.s_addr = address,
162 : };
163 0 : _cleanup_close_ int s = -1;
164 0 : int r, on = 1, tos = IPTOS_CLASS_CS6;
165 :
166 0 : s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
167 0 : if (s < 0)
168 0 : return -errno;
169 :
170 0 : r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
171 0 : if (r < 0)
172 0 : return -errno;
173 :
174 0 : r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
175 0 : if (r < 0)
176 0 : return -errno;
177 :
178 0 : if (address == INADDR_ANY) {
179 0 : r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
180 0 : if (r < 0)
181 0 : return -errno;
182 :
183 0 : r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on));
184 0 : if (r < 0)
185 0 : return -errno;
186 : } else {
187 0 : r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &on, sizeof(on));
188 0 : if (r < 0)
189 0 : return -errno;
190 : }
191 :
192 0 : r = bind(s, &src.sa, sizeof(src.in));
193 0 : if (r < 0)
194 0 : return -errno;
195 :
196 0 : r = s;
197 0 : s = -1;
198 :
199 0 : return r;
200 : }
201 :
202 0 : int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
203 : const void *packet, size_t len) {
204 : int r;
205 :
206 0 : assert(link);
207 0 : assert(packet);
208 0 : assert(len);
209 :
210 0 : r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll));
211 0 : if (r < 0)
212 0 : return -errno;
213 :
214 0 : return 0;
215 : }
216 :
217 0 : int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
218 : const void *packet, size_t len) {
219 0 : union sockaddr_union dest = {
220 : .in.sin_family = AF_INET,
221 0 : .in.sin_port = htobe16(port),
222 : .in.sin_addr.s_addr = address,
223 : };
224 : int r;
225 :
226 0 : assert(s >= 0);
227 0 : assert(packet);
228 0 : assert(len);
229 :
230 0 : r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in));
231 0 : if (r < 0)
232 0 : return -errno;
233 :
234 0 : return 0;
235 : }
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