mirror of
https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git
synced 2026-01-27 14:50:27 +01:00
9ac1d6e22b
When creating the socket for listening to LLDP frames we are setting NM_ETHERTYPE_LLDP (0x88cc) as protocol. In most of the cases, that is correct but when the interface is attached as a port to a OVS bridge, kernel is not matching the protocol correctly. The reason might be that some metadata is added to the packet, but we are not completely sure about it. Instead, we should use ETH_P_ALL to match all the protocols. Later, we have a eBPF filter to drop the packet by multicast MAC address or protocol. This is how lldpd is doing it for example. https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1903
74 lines
2.9 KiB
C
74 lines
2.9 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include "libnm-glib-aux/nm-default-glib-i18n-lib.h"
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#include "nm-lldp-network.h"
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#include <linux/filter.h>
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#include <linux/if_packet.h>
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#include <netinet/if_ether.h>
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int
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nm_lldp_network_bind_raw_socket(int ifindex)
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{
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static const struct sock_filter filter[] = {
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BPF_STMT(BPF_LD + BPF_W + BPF_ABS,
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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,
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offsetof(struct ethhdr, h_dest)
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+ 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, NM_ETHERTYPE_LLDP, 1, 0), /* A != NM_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_MAX), /* accept packet */
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};
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static const struct sock_fprog fprog = {
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.len = G_N_ELEMENTS(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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struct sockaddr_ll saddrll = {
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.sll_family = AF_PACKET,
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.sll_ifindex = ifindex,
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};
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nm_auto_close int fd = -1;
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assert(ifindex > 0);
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fd = socket(AF_PACKET, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, htobe16(ETH_P_ALL));
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if (fd < 0)
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return -errno;
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if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0)
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return -errno;
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/* customer bridge */
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if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
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return -errno;
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/* non TPMR bridge */
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mreq.mr_address[ETH_ALEN - 1] = 0x03;
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if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
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return -errno;
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/* nearest bridge */
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mreq.mr_address[ETH_ALEN - 1] = 0x0E;
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if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
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return -errno;
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if (bind(fd, (const struct sockaddr *) &saddrll, sizeof(saddrll)) < 0)
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return -errno;
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return nm_steal_fd(&fd);
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}
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