[thirdparty/systemd.git] / src / libsystemd-network / lldp-network.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <linux/filter.h>

#include "fd-util.h"
#include "lldp-network.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, ETH_P_LLDP, 1, 0),                    /* A != ETH_P_LLDP */
                BPF_STMT(BPF_RET + BPF_K, 0),                                             /* drop packet */
                BPF_STMT(BPF_RET + BPF_K, UINT32_MAX),                                    /* 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 = -EBADF;

        assert(ifindex > 0);

        fd = socket(AF_PACKET, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK,
                    htobe16(ETH_P_LLDP));
        if (fd < 0)
                return -errno;

        if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0)
                return -errno;

        /* customer bridge */
        if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
                return -errno;

        /* non TPMR bridge */
        mreq.mr_address[ETH_ALEN - 1] = 0x03;
        if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
                return -errno;

        /* nearest bridge */
        mreq.mr_address[ETH_ALEN - 1] = 0x0E;
        if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
                return -errno;

        if (bind(fd, &saddrll.sa, sizeof(saddrll.ll)) < 0)
                return -errno;

        return TAKE_FD(fd);
}
Commit	Line	Data
	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
	2
	3	#include <linux/filter.h>
	4
	5	#include "fd-util.h"
	6	#include "lldp-network.h"
	7	#include "socket-util.h"
	8
	9	int lldp_network_bind_raw_socket(int ifindex) {
	10	static const struct sock_filter filter[] = {
	11	BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ethhdr, h_dest)), /* A <- 4 bytes of destination MAC */
	12	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0), /* A != 01:80:c2:00 */
	13	BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
	14	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_dest) + 4), /* A <- remaining 2 bytes of destination MAC */
	15	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0), /* A != 00:00 */
	16	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0), /* A != 00:03 */
	17	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0), /* A != 00:0e */
	18	BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
	19	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_proto)), /* A <- protocol */
	20	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_P_LLDP, 1, 0), /* A != ETH_P_LLDP */
	21	BPF_STMT(BPF_RET + BPF_K, 0), /* drop packet */
	22	BPF_STMT(BPF_RET + BPF_K, UINT32_MAX), /* accept packet */
	23	};
	24	static const struct sock_fprog fprog = {
	25	.len = ELEMENTSOF(filter),
	26	.filter = (struct sock_filter*) filter,
	27	};
	28	struct packet_mreq mreq = {
	29	.mr_ifindex = ifindex,
	30	.mr_type = PACKET_MR_MULTICAST,
	31	.mr_alen = ETH_ALEN,
	32	.mr_address = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 }
	33	};
	34	union sockaddr_union saddrll = {
	35	.ll.sll_family = AF_PACKET,
	36	.ll.sll_ifindex = ifindex,
	37	};
	38	_cleanup_close_ int fd = -EBADF;
	39
	40	assert(ifindex > 0);
	41
	42	fd = socket(AF_PACKET, SOCK_RAW\|SOCK_CLOEXEC\|SOCK_NONBLOCK,
	43	htobe16(ETH_P_LLDP));
	44	if (fd < 0)
	45	return -errno;
	46
	47	if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0)
	48	return -errno;
	49
	50	/* customer bridge */
	51	if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
	52	return -errno;
	53
	54	/* non TPMR bridge */
	55	mreq.mr_address[ETH_ALEN - 1] = 0x03;
	56	if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
	57	return -errno;
	58
	59	/* nearest bridge */
	60	mreq.mr_address[ETH_ALEN - 1] = 0x0E;
	61	if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
	62	return -errno;
	63
	64	if (bind(fd, &saddrll.sa, sizeof(saddrll.ll)) < 0)
	65	return -errno;
	66
	67	return TAKE_FD(fd);
	68	}