lldp-tlv.c revision a7f7d1bde43fc825c49afea3f946f5b4b3d563e0
/*-*- 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 <net/ethernet.h>
#include <arpa/inet.h>
#include "macro.h"
#include "lldp-tlv.h"
int tlv_section_new(tlv_section **ret) {
tlv_section *s;
s = new0(tlv_section, 1);
if (!s)
return -ENOMEM;
*ret = s;
return 0;
}
void tlv_section_free(tlv_section *m) {
if (!m)
return;
free(m);
}
int tlv_packet_new(tlv_packet **ret) {
tlv_packet *m;
m = new0(tlv_packet, 1);
if (!m)
return -ENOMEM;
LIST_HEAD_INIT(m->sections);
*ret = m;
return 0;
}
void tlv_packet_free(tlv_packet *m) {
tlv_section *s, *n;
if (!m)
return;
LIST_FOREACH_SAFE(section, s, n, m->sections)
tlv_section_free(s);
free(m);
}
int tlv_packet_append_bytes(tlv_packet *m, const void *data, size_t data_length) {
uint8_t *p;
assert_return(m, -EINVAL);
assert_return(data, -EINVAL);
assert_return(data_length, -EINVAL);
if (m->length + data_length > ETHER_MAX_LEN)
return -ENOMEM;
p = m->pdu + m->length;
memcpy(p, data, data_length);
m->length += data_length;
return 0;
}
int tlv_packet_append_u8(tlv_packet *m, uint8_t data) {
assert_return(m, -EINVAL);
return tlv_packet_append_bytes(m, &data, sizeof(uint8_t));
}
int tlv_packet_append_u16(tlv_packet *m, uint16_t data) {
uint16_t type;
assert_return(m, -EINVAL);
type = htons(data);
return tlv_packet_append_bytes(m, &type, sizeof(uint16_t));
}
int tlv_packet_append_u32(tlv_packet *m, uint32_t data) {
uint32_t type;
assert_return(m, -EINVAL);
type = htonl(data);
return tlv_packet_append_bytes(m, &type, sizeof(uint32_t));
}
int tlv_packet_append_string(tlv_packet *m, char *data, uint16_t size) {
assert_return(m, -EINVAL);
return tlv_packet_append_bytes(m, data, size);
}
int lldp_tlv_packet_open_container(tlv_packet *m, uint16_t type) {
assert_return(m, -EINVAL);
m->container_pos = m->pdu + m->length;
return tlv_packet_append_u16(m, type << 9);
}
int lldp_tlv_packet_close_container(tlv_packet *m) {
uint16_t type;
assert_return(m, -EINVAL);
assert_return(m->container_pos, -EINVAL);
memcpy(&type, m->container_pos, sizeof(uint16_t));
type |= htons(((m->pdu + m->length) - (m->container_pos + 2)) & 0x01ff);
memcpy(m->container_pos, &type, sizeof(uint16_t));
return 0;
}
static inline int tlv_packet_read_internal(tlv_section *m, void **data) {
assert_return(m->read_pos, -EINVAL);
*data = m->read_pos;
return 0;
}
int tlv_packet_read_u8(tlv_packet *m, uint8_t *data) {
void *val = NULL;
int r;
assert_return(m, -EINVAL);
r = tlv_packet_read_internal(m->container, &val);
if (r < 0)
return r;
memcpy(data, val, sizeof(uint8_t));
m->container->read_pos ++;
return 0;
}
int tlv_packet_read_u16(tlv_packet *m, uint16_t *data) {
uint16_t t;
void *val = NULL;
int r;
assert_return(m, -EINVAL);
r = tlv_packet_read_internal(m->container, &val);
if (r < 0)
return r;
memcpy(&t, val, sizeof(uint16_t));
*data = ntohs(t);
m->container->read_pos += 2;
return 0;
}
int tlv_packet_read_u32(tlv_packet *m, uint32_t *data) {
uint32_t t;
void *val;
int r;
assert_return(m, -EINVAL);
r = tlv_packet_read_internal(m->container, &val);
if (r < 0)
return r;
memcpy(&t, val, sizeof(uint32_t));
*data = ntohl(t);
m->container->read_pos += 4;
return r;
}
int tlv_packet_read_string(tlv_packet *m, char **data, uint16_t *data_length) {
void *val = NULL;
int r;
assert_return(m, -EINVAL);
r = tlv_packet_read_internal(m->container, &val);
if (r < 0)
return r;
*data = (char *) val;
*data_length = m->container->length;
m->container->read_pos += m->container->length;
return 0;
}
int tlv_packet_read_bytes(tlv_packet *m, uint8_t **data, uint16_t *data_length) {
void *val = NULL;
int r;
assert_return(m, -EINVAL);
r = tlv_packet_read_internal(m->container, &val);
if (r < 0)
return r;
*data = (uint8_t *) val;
*data_length = m->container->length;
m->container->read_pos += m->container->length;
return 0;
}
/* parse raw TLV packet */
int tlv_packet_parse_pdu(tlv_packet *m, uint16_t size) {
tlv_section *section, *tail;
uint16_t t, l;
uint8_t *p;
int r;
assert_return(m, -EINVAL);
assert_return(size, -EINVAL);
p = m->pdu;
/* extract ethernet herader */
memcpy(&m->mac, p, ETH_ALEN);
p += sizeof(struct ether_header);
for (l = 0; l <= size; ) {
r = tlv_section_new(&section);
if (r < 0)
return r;
memcpy(&t, p, sizeof(uint16_t));
section->type = ntohs(t) >> 9;
section->length = ntohs(t) & 0x01ff;
if (section->type == LLDP_TYPE_END || section->type >=_LLDP_TYPE_MAX) {
tlv_section_free(section);
break;
}
p += 2;
section->data = p;
LIST_FIND_TAIL(section, m->sections, tail);
LIST_INSERT_AFTER(section, m->sections, tail, section);
p += section->length;
l += (section->length + 2);
}
return 0;
}
int lldp_tlv_packet_enter_container(tlv_packet *m, uint16_t type) {
tlv_section *s;
assert_return(m, -EINVAL);
LIST_FOREACH(section, s, m->sections)
if (s->type == type)
break;
if (!s)
return -1;
m->container = s;
m->container->read_pos = s->data;
if (!m->container->read_pos) {
m->container = 0;
return -1;
}
return 0;
}
int lldp_tlv_packet_exit_container(tlv_packet *m) {
assert_return(m, -EINVAL);
m->container = 0;
return 0;
}