From 19f4f86bfed21c5326ed2acebe1163f3a83e832b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 04:25:50 +0200 Subject: Adding upstream version 241. Signed-off-by: Daniel Baumann --- src/libsystemd-network/lldp-network.c | 78 +++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 src/libsystemd-network/lldp-network.c (limited to 'src/libsystemd-network/lldp-network.c') diff --git a/src/libsystemd-network/lldp-network.c b/src/libsystemd-network/lldp-network.c new file mode 100644 index 0000000..870584c --- /dev/null +++ b/src/libsystemd-network/lldp-network.c @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include +#include + +#include "fd-util.h" +#include "lldp-network.h" +#include "missing.h" +#include "socket-util.h" + +int lldp_network_bind_raw_socket(int ifindex) { + + static const struct sock_filter filter[] = { + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ethhdr, h_dest)), /* A <- 4 bytes of destination MAC */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0), /* A != 01:80:c2:00 */ + BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0), /* A != 00:00 */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0), /* A != 00:03 */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0), /* A != 00:0e */ + BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_proto)), /* A <- protocol */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_LLDP, 1, 0), /* A != ETHERTYPE_LLDP */ + BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */ + BPF_STMT(BPF_RET + BPF_K, (uint32_t) -1), /* accept packet */ + }; + + static const struct sock_fprog fprog = { + .len = ELEMENTSOF(filter), + .filter = (struct sock_filter*) filter, + }; + + struct packet_mreq mreq = { + .mr_ifindex = ifindex, + .mr_type = PACKET_MR_MULTICAST, + .mr_alen = ETH_ALEN, + .mr_address = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 } + }; + + union sockaddr_union saddrll = { + .ll.sll_family = AF_PACKET, + .ll.sll_ifindex = ifindex, + }; + + _cleanup_close_ int fd = -1; + int r; + + assert(ifindex > 0); + + fd = socket(PF_PACKET, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, + htobe16(ETHERTYPE_LLDP)); + if (fd < 0) + return -errno; + + r = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); + if (r < 0) + return -errno; + + r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); + if (r < 0) + return -errno; + + mreq.mr_address[ETH_ALEN - 1] = 0x03; + r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); + if (r < 0) + return -errno; + + mreq.mr_address[ETH_ALEN - 1] = 0x0E; + r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); + if (r < 0) + return -errno; + + r = bind(fd, &saddrll.sa, sizeof(saddrll.ll)); + if (r < 0) + return -errno; + + return TAKE_FD(fd); +} -- cgit v1.2.3