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8b4a9693 PF |
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/types.h> | |
22 | #include <sys/socket.h> | |
23 | #include <string.h> | |
24 | #include <linux/if_packet.h> | |
25 | #include <net/ethernet.h> | |
7429b07f | 26 | #include <net/if_arp.h> |
8b4a9693 PF |
27 | #include <stdio.h> |
28 | #include <unistd.h> | |
bc29e507 | 29 | #include <linux/filter.h> |
8b4a9693 PF |
30 | |
31 | #include "socket-util.h" | |
32 | ||
33 | #include "dhcp-internal.h" | |
34 | ||
088b6ba2 | 35 | int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, |
58587a7a | 36 | uint32_t xid, struct ether_addr mac_addr) { |
088b6ba2 | 37 | |
bc29e507 | 38 | struct sock_filter filter[] = { |
088b6ba2 LP |
39 | BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ |
40 | BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */ | |
41 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
42 | BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */ | |
43 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */ | |
44 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
45 | BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */ | |
46 | BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */ | |
47 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ | |
48 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
49 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */ | |
50 | BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */ | |
51 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ | |
52 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
53 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */ | |
54 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */ | |
55 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
56 | BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */ | |
57 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */ | |
58 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
59 | BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */ | |
60 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header type == ARPHRD_ETHER ? */ | |
61 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
62 | BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- mac address length */ | |
63 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHER_ADDR_LEN, 1, 0), /* address length == ETHER_ADDR_LEN ? */ | |
64 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
65 | BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */ | |
66 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */ | |
67 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
68 | BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) &mac_addr))), /* A <- 4 bytes of client's MAC */ | |
69 | BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ | |
70 | BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */ | |
71 | BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ | |
72 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ | |
73 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
74 | BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) &mac_addr) + 4)))), /* A <- remainder of client's MAC */ | |
75 | BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ | |
76 | BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */ | |
77 | BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ | |
78 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ | |
79 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
80 | BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */ | |
81 | BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */ | |
82 | BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ | |
83 | BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ | |
bc29e507 TG |
84 | }; |
85 | struct sock_fprog fprog = { | |
088b6ba2 LP |
86 | .len = ELEMENTSOF(filter), |
87 | .filter = filter | |
bc29e507 | 88 | }; |
c3d2994b | 89 | _cleanup_close_ int s = -1; |
fef0e0f3 | 90 | int r, on = 1; |
8b4a9693 | 91 | |
088b6ba2 | 92 | assert(ifindex > 0); |
23f30ed3 TG |
93 | assert(link); |
94 | ||
66a67eff | 95 | s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
8b4a9693 PF |
96 | if (s < 0) |
97 | return -errno; | |
98 | ||
088b6ba2 | 99 | r = setsockopt(s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on)); |
c3d2994b TG |
100 | if (r < 0) |
101 | return -errno; | |
102 | ||
103 | r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); | |
104 | if (r < 0) | |
105 | return -errno; | |
106 | ||
8c00042c PF |
107 | link->ll.sll_family = AF_PACKET; |
108 | link->ll.sll_protocol = htons(ETH_P_IP); | |
088b6ba2 | 109 | link->ll.sll_ifindex = ifindex; |
8c00042c PF |
110 | link->ll.sll_halen = ETH_ALEN; |
111 | memset(link->ll.sll_addr, 0xff, ETH_ALEN); | |
8b4a9693 | 112 | |
c3d2994b TG |
113 | r = bind(s, &link->sa, sizeof(link->ll)); |
114 | if (r < 0) | |
bc29e507 | 115 | return -errno; |
bc29e507 | 116 | |
c3d2994b TG |
117 | r = s; |
118 | s = -1; | |
8b4a9693 | 119 | |
c3d2994b | 120 | return r; |
8c00042c PF |
121 | } |
122 | ||
c3d2994b | 123 | int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) { |
234fc2df PF |
124 | union sockaddr_union src = { |
125 | .in.sin_family = AF_INET, | |
080ab276 TG |
126 | .in.sin_port = htobe16(port), |
127 | .in.sin_addr.s_addr = address, | |
234fc2df | 128 | }; |
c3d2994b | 129 | _cleanup_close_ int s = -1; |
076adf01 | 130 | int r, on = 1, tos = IPTOS_CLASS_CS6; |
234fc2df PF |
131 | |
132 | s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); | |
133 | if (s < 0) | |
134 | return -errno; | |
135 | ||
c3d2994b TG |
136 | r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); |
137 | if (r < 0) | |
85923f79 | 138 | return -errno; |
b44cd882 | 139 | |
076adf01 TG |
140 | r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); |
141 | if (r < 0) | |
142 | return -errno; | |
fef0e0f3 | 143 | |
076adf01 | 144 | if (address == INADDR_ANY) { |
fef0e0f3 TG |
145 | r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on)); |
146 | if (r < 0) | |
147 | return -errno; | |
d6bd972d TG |
148 | |
149 | r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)); | |
150 | if (r < 0) | |
151 | return -errno; | |
076adf01 TG |
152 | } else { |
153 | r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &on, sizeof(on)); | |
154 | if (r < 0) | |
155 | return -errno; | |
fef0e0f3 | 156 | } |
85923f79 | 157 | |
c3d2994b TG |
158 | r = bind(s, &src.sa, sizeof(src.in)); |
159 | if (r < 0) | |
234fc2df | 160 | return -errno; |
234fc2df | 161 | |
c3d2994b TG |
162 | r = s; |
163 | s = -1; | |
164 | ||
165 | return r; | |
234fc2df PF |
166 | } |
167 | ||
8c00042c | 168 | int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, |
c3d2994b TG |
169 | const void *packet, size_t len) { |
170 | int r; | |
171 | ||
23f30ed3 TG |
172 | assert(link); |
173 | assert(packet); | |
174 | assert(len); | |
175 | ||
c3d2994b TG |
176 | r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll)); |
177 | if (r < 0) | |
1c8035a8 | 178 | return -errno; |
8b4a9693 | 179 | |
1c8035a8 | 180 | return 0; |
8b4a9693 | 181 | } |
234fc2df | 182 | |
080ab276 | 183 | int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port, |
c3d2994b | 184 | const void *packet, size_t len) { |
234fc2df PF |
185 | union sockaddr_union dest = { |
186 | .in.sin_family = AF_INET, | |
080ab276 TG |
187 | .in.sin_port = htobe16(port), |
188 | .in.sin_addr.s_addr = address, | |
234fc2df | 189 | }; |
c3d2994b TG |
190 | int r; |
191 | ||
192 | assert(s >= 0); | |
193 | assert(packet); | |
194 | assert(len); | |
234fc2df | 195 | |
c3d2994b TG |
196 | r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)); |
197 | if (r < 0) | |
234fc2df PF |
198 | return -errno; |
199 | ||
200 | return 0; | |
201 | } |