11a1589223
Files which are installed as-is (any .service and other unit files, .conf files, .policy files, etc), are left as is. My assumption is that SPDX identifiers are not yet that well known, so it's better to retain the extended header to avoid any doubt. I also kept any copyright lines. We can probably remove them, but it'd nice to obtain explicit acks from all involved authors before doing that.
84 lines
3.2 KiB
C
84 lines
3.2 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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This file is part of systemd.
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Copyright (C) 2014 Tom Gundersen
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Copyright (C) 2014 Susant Sahani
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***/
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#include <linux/filter.h>
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#include <netinet/if_ether.h>
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#include "fd-util.h"
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#include "lldp-network.h"
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#include "socket-util.h"
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int lldp_network_bind_raw_socket(int ifindex) {
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static const struct sock_filter filter[] = {
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BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ethhdr, h_dest)), /* A <- 4 bytes of destination MAC */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0), /* A != 01:80:c2:00 */
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BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0), /* A != 00:00 */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0), /* A != 00:03 */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0), /* A != 00:0e */
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BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_proto)), /* A <- protocol */
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_LLDP, 1, 0), /* A != ETHERTYPE_LLDP */
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BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
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BPF_STMT(BPF_RET + BPF_K, (uint32_t) -1), /* accept packet */
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};
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static const struct sock_fprog fprog = {
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.len = ELEMENTSOF(filter),
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.filter = (struct sock_filter*) filter,
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};
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struct packet_mreq mreq = {
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.mr_ifindex = ifindex,
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.mr_type = PACKET_MR_MULTICAST,
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.mr_alen = ETH_ALEN,
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.mr_address = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 }
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};
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union sockaddr_union saddrll = {
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.ll.sll_family = AF_PACKET,
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.ll.sll_ifindex = ifindex,
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};
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_cleanup_close_ int fd = -1;
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int r;
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assert(ifindex > 0);
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fd = socket(PF_PACKET, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK,
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htobe16(ETHERTYPE_LLDP));
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if (fd < 0)
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return -errno;
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r = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
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if (r < 0)
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return -errno;
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r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
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if (r < 0)
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return -errno;
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mreq.mr_address[ETH_ALEN - 1] = 0x03;
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r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
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if (r < 0)
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return -errno;
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mreq.mr_address[ETH_ALEN - 1] = 0x0E;
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r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
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if (r < 0)
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return -errno;
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r = bind(fd, &saddrll.sa, sizeof(saddrll.ll));
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if (r < 0)
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return -errno;
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return TAKE_FD(fd);
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}
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