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sys/netlink/netlink_message_parser.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <machine/stdarg.h>
#include <net/if.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/route/route_ctl.h>
#include <netlink/netlink.h>
#include <netlink/netlink_ctl.h>
#include <netlink/netlink_var.h>
#include <netlink/netlink_route.h>
#define DEBUG_MOD_NAME nl_parser
#define DEBUG_MAX_LEVEL LOG_DEBUG3
#include <netlink/netlink_debug.h>
_DECLARE_DEBUG(LOG_DEBUG);
bool
nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...)
{
va_list ap;
if (npt->err_msg != NULL)
return (false);
char *buf = npt_alloc(npt, NL_MAX_ERROR_BUF);
if (buf == NULL)
return (false);
va_start(ap, fmt);
vsnprintf(buf, NL_MAX_ERROR_BUF, fmt, ap);
va_end(ap);
npt->err_msg = buf;
return (true);
}
bool
nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off)
{
if (npt->err_off != 0)
return (false);
npt->err_off = off;
return (true);
}
static const struct nlattr_parser *
search_states(const struct nlattr_parser *ps, int pslen, int key)
{
int left_i = 0, right_i = pslen - 1;
if (key < ps[0].type || key > ps[pslen - 1].type)
return (NULL);
while (left_i + 1 < right_i) {
int mid_i = (left_i + right_i) / 2;
if (key < ps[mid_i].type)
right_i = mid_i;
else if (key > ps[mid_i].type)
left_i = mid_i + 1;
else
return (&ps[mid_i]);
}
if (ps[left_i].type == key)
return (&ps[left_i]);
else if (ps[right_i].type == key)
return (&ps[right_i]);
return (NULL);
}
int
nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, int pslen,
struct nl_pstate *npt, void *target)
{
struct nlattr *nla = NULL;
int error = 0;
NL_LOG(LOG_DEBUG3, "parse %p remaining_len %d", nla_head, len);
int orig_len = len;
NLA_FOREACH(nla, nla_head, len) {
NL_LOG(LOG_DEBUG3, ">> parsing %p attr_type %d len %d (rem %d)", nla, nla->nla_type, nla->nla_len, len);
if (nla->nla_len < sizeof(struct nlattr)) {
NLMSG_REPORT_ERR_MSG(npt, "Invalid attr %p type %d len: %d",
nla, nla->nla_type, nla->nla_len);
uint32_t off = (char *)nla - (char *)npt->hdr;
nlmsg_report_err_offset(npt, off);
return (EINVAL);
}
int nla_type = nla->nla_type & NLA_TYPE_MASK;
const struct nlattr_parser *s = search_states(ps, pslen, nla_type);
if (s != NULL) {
void *ptr = (void *)((char *)target + s->off);
error = s->cb(nla, npt, s->arg, ptr);
if (error != 0) {
uint32_t off = (char *)nla - (char *)npt->hdr;
nlmsg_report_err_offset(npt, off);
NL_LOG(LOG_DEBUG3, "parse failed att offset %u", off);
return (error);
}
} else {
/* Ignore non-specified attributes */
NL_LOG(LOG_DEBUG3, "ignoring attr %d", nla->nla_type);
}
}
if (len >= sizeof(struct nlattr)) {
nla = (struct nlattr *)((char *)nla_head + (orig_len - len));
NL_LOG(LOG_DEBUG3, " >>> end %p attr_type %d len %d", nla,
nla->nla_type, nla->nla_len);
}
NL_LOG(LOG_DEBUG3, "end parse: %p remaining_len %d", nla, len);
return (0);
}
int
nl_parse_attrs(struct nlmsghdr *hdr, int hdrlen, struct nlattr_parser *ps, int pslen,
struct nl_pstate *npt, void *target)
{
int off = NLMSG_HDRLEN + NETLINK_ALIGN(hdrlen);
int len = hdr->nlmsg_len - off;
struct nlattr *nla_head = (struct nlattr *)((char *)hdr + off);
return (nl_parse_attrs_raw(nla_head, len, ps, pslen, npt, target));
}
int
nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
if (__predict_false(NLA_DATA_LEN(nla) != 0)) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not a flag",
nla->nla_type, NLA_DATA_LEN(nla));
return (EINVAL);
}
*((uint8_t *)target) = 1;
return (0);
}
static struct sockaddr *
parse_rta_ip4(void *rta_data, struct nl_pstate *npt, int *perror)
{
struct sockaddr_in *sin;
sin = (struct sockaddr_in *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in));
if (__predict_false(sin == NULL)) {
*perror = ENOBUFS;
return (NULL);
}
sin->sin_len = sizeof(struct sockaddr_in);
sin->sin_family = AF_INET;
memcpy(&sin->sin_addr, rta_data, sizeof(struct in_addr));
return ((struct sockaddr *)sin);
}
static struct sockaddr *
parse_rta_ip6(void *rta_data, struct nl_pstate *npt, int *perror)
{
struct sockaddr_in6 *sin6;
sin6 = (struct sockaddr_in6 *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in6));
if (__predict_false(sin6 == NULL)) {
*perror = ENOBUFS;
return (NULL);
}
sin6->sin6_len = sizeof(struct sockaddr_in6);
sin6->sin6_family = AF_INET6;
memcpy(&sin6->sin6_addr, rta_data, sizeof(struct in6_addr));
return ((struct sockaddr *)sin6);
}
static struct sockaddr *
parse_rta_ip(struct rtattr *rta, struct nl_pstate *npt, int *perror)
{
void *rta_data = NL_RTA_DATA(rta);
int rta_len = NL_RTA_DATA_LEN(rta);
if (rta_len == sizeof(struct in_addr)) {
return (parse_rta_ip4(rta_data, npt, perror));
} else if (rta_len == sizeof(struct in6_addr)) {
return (parse_rta_ip6(rta_data, npt, perror));
} else {
NLMSG_REPORT_ERR_MSG(npt, "unknown IP len: %d for rta type %d",
rta_len, rta->rta_type);
*perror = ENOTSUP;
return (NULL);
}
return (NULL);
}
int
nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
int error = 0;
struct sockaddr *sa = parse_rta_ip((struct rtattr *)nla, npt, &error);
*((struct sockaddr **)target) = sa;
return (error);
}
static struct sockaddr *
parse_rta_via(struct rtattr *rta, struct nl_pstate *npt, int *perror)
{
struct rtvia *via = NL_RTA_DATA(rta);
int data_len = NL_RTA_DATA_LEN(rta);
if (__predict_false(data_len) < sizeof(struct rtvia)) {
NLMSG_REPORT_ERR_MSG(npt, "undersized RTA_VIA(%d) attr: len %d",
rta->rta_type, data_len);
*perror = EINVAL;
return (NULL);
}
data_len -= offsetof(struct rtvia, rtvia_addr);
switch (via->rtvia_family) {
case AF_INET:
if (__predict_false(data_len < sizeof(struct in_addr))) {
*perror = EINVAL;
return (NULL);
}
return (parse_rta_ip4(via->rtvia_addr, npt, perror));
case AF_INET6:
if (__predict_false(data_len < sizeof(struct in6_addr))) {
*perror = EINVAL;
return (NULL);
}
return (parse_rta_ip6(via->rtvia_addr, npt, perror));
default:
*perror = ENOTSUP;
return (NULL);
}
}
int
nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
int error = 0;
struct sockaddr *sa = parse_rta_via((struct rtattr *)nla, npt, &error);
*((struct sockaddr **)target) = sa;
return (error);
}
int
nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint16_t))) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
nla->nla_type, NLA_DATA_LEN(nla));
return (EINVAL);
}
*((uint16_t *)target) = *((const uint16_t *)NL_RTA_DATA_CONST(nla));
return (0);
}
int
nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
nla->nla_type, NLA_DATA_LEN(nla));
return (EINVAL);
}
*((uint32_t *)target) = *((const uint32_t *)NL_RTA_DATA_CONST(nla));
return (0);
}
int
nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint64_t))) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint64",
nla->nla_type, NLA_DATA_LEN(nla));
return (EINVAL);
}
memcpy(target, NL_RTA_DATA_CONST(nla), sizeof(uint64_t));
return (0);
}
static int
nlattr_get_ifp_internal(struct nlattr *nla, struct nl_pstate *npt,
void *target, bool zero_ok)
{
if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
nla->nla_type, NLA_DATA_LEN(nla));
return (EINVAL);
}
uint32_t ifindex = *((const uint32_t *)NLA_DATA_CONST(nla));
if (ifindex == 0 && zero_ok) {
*((struct ifnet **)target) = NULL;
return (0);
}
NET_EPOCH_ASSERT();
struct ifnet *ifp = ifnet_byindex(ifindex);
if (__predict_false(ifp == NULL)) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d: ifindex %u invalid",
nla->nla_type, ifindex);
return (ENOENT);
}
*((struct ifnet **)target) = ifp;
NL_LOG(LOG_DEBUG3, "nla type %d: ifindex %u -> %s", nla->nla_type,
ifindex, if_name(ifp));
return (0);
}
int
nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
return (nlattr_get_ifp_internal(nla, npt, target, false));
}
int
nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
return (nlattr_get_ifp_internal(nla, npt, target, true));
}
int
nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
int maxlen = NLA_DATA_LEN(nla);
if (__predict_false(strnlen((char *)NLA_DATA(nla), maxlen) >= maxlen)) {
NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not NULL-terminated",
nla->nla_type, maxlen);
return (EINVAL);
}
*((char **)target) = (char *)NLA_DATA(nla);
return (0);
}
int
nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
int maxlen = NLA_DATA_LEN(nla);
char *buf = npt_alloc(npt, maxlen + 1);
if (buf == NULL)
return (ENOMEM);
buf[maxlen] = '\0';
memcpy(buf, NLA_DATA(nla), maxlen);
*((char **)target) = buf;
return (0);
}
int
nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
NL_LOG(LOG_DEBUG3, "STORING %p len %d", nla, nla->nla_len);
*((struct nlattr **)target) = nla;
return (0);
}
int
nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
{
const struct nlhdr_parser *p = (const struct nlhdr_parser *)arg;
int error;
/* Assumes target points to the beginning of the structure */
error = nl_parse_header(NLA_DATA(nla), NLA_DATA_LEN(nla), p, npt, target);
return (error);
}
int
nlf_get_ifp(void *src, struct nl_pstate *npt, void *target)
{
int ifindex = *((const int *)src);
NET_EPOCH_ASSERT();
struct ifnet *ifp = ifnet_byindex(ifindex);
if (ifp == NULL) {
NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
return (ENOENT);
}
*((struct ifnet **)target) = ifp;
return (0);
}
int
nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target)
{
int ifindex = *((const int *)src);
NET_EPOCH_ASSERT();
struct ifnet *ifp = ifnet_byindex(ifindex);
if (ifindex != 0 && ifp == NULL) {
NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
return (ENOENT);
}
*((struct ifnet **)target) = ifp;
return (0);
}
int
nlf_get_u8(void *src, struct nl_pstate *npt, void *target)
{
uint8_t val = *((const uint8_t *)src);
*((uint8_t *)target) = val;
return (0);
}
int
nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target)
{
*((uint32_t *)target) = *((const uint8_t *)src);
return (0);
}
int
nlf_get_u16(void *src, struct nl_pstate *npt, void *target)
{
*((uint16_t *)target) = *((const uint16_t *)src);
return (0);
}
int
nlf_get_u32(void *src, struct nl_pstate *npt, void *target)
{
*((uint32_t *)target) = *((const uint32_t *)src);
return (0);
}