diff options
Diffstat (limited to 'src/libsystemd-network/lldp-network.c')
| -rw-r--r-- | src/libsystemd-network/lldp-network.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/src/libsystemd-network/lldp-network.c b/src/libsystemd-network/lldp-network.c new file mode 100644 index 0000000000..cfab91146c --- /dev/null +++ b/src/libsystemd-network/lldp-network.c @@ -0,0 +1,111 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright (C) 2014 Tom Gundersen + Copyright (C) 2014 Susant Sahani + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <linux/filter.h> +#include <linux/if_ether.h> + +#include "socket-util.h" +#include "lldp-tlv.h" +#include "lldp-network.h" +#include "sd-lldp.h" + +int lldp_network_bind_raw_socket(int ifindex) { + typedef struct LLDPFrame { + struct ethhdr hdr; + uint8_t tlvs[0]; + } LLDPFrame; + + struct sock_filter filter[] = { + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(LLDPFrame, hdr.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(LLDPFrame, hdr.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(LLDPFrame, hdr.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 */ + }; + + struct sock_fprog fprog = { + .len = ELEMENTSOF(filter), + .filter = filter + }; + + _cleanup_close_ int s = -1; + + union sockaddr_union saddrll = { + .ll.sll_family = AF_PACKET, + .ll.sll_ifindex = ifindex, + }; + + int r; + + assert(ifindex > 0); + + s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); + if (s < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); + if (r < 0) + return -errno; + + r = bind(s, &saddrll.sa, sizeof(saddrll.ll)); + if (r < 0) + return -errno; + + r = s; + s = -1; + + return r; +} + +int lldp_receive_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_tlv_packet_free_ tlv_packet *packet = NULL; + tlv_packet *p; + uint16_t length; + int r; + + assert(fd); + assert(userdata); + + r = tlv_packet_new(&packet); + if (r < 0) + return r; + + length = read(fd, &packet->pdu, sizeof(packet->pdu)); + + /* Silently drop the packet */ + if ((size_t) length > ETHER_MAX_LEN) + return 0; + + packet->userdata = userdata; + + p = packet; + packet = NULL; + + return lldp_handle_packet(p, (uint16_t) length); +} |