mir/ovs
2
0
Fork 0
mirror of https://github.com/openvswitch/ovs synced 2025-08-29 05:18:13 +00:00
Code Issues Releases Wiki Activity
ovs/lib/packets.c
Ben Pfaff 2b02db1b4c packets: Add new functions for IPv4 and IPv6 address parsing. 
These will be used in an upcoming patch to reduce duplicated code.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>
2015-12-15 18:00:21 -08:00

1295 lines
39 KiB
C
Raw Blame History

/*
* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "packets.h"
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <stdlib.h>
#include "byte-order.h"
#include "csum.h"
#include "crc32c.h"
#include "flow.h"
#include "hmap.h"
#include "dynamic-string.h"
#include "ovs-thread.h"
#include "odp-util.h"
#include "dp-packet.h"
#include "unaligned.h"
const struct in6_addr in6addr_exact = IN6ADDR_EXACT_INIT;
const struct in6_addr in6addr_all_hosts = IN6ADDR_ALL_HOSTS_INIT;
struct in6_addr
flow_tnl_dst(const struct flow_tnl *tnl)
{
return tnl->ip_dst ? in6_addr_mapped_ipv4(tnl->ip_dst) : tnl->ipv6_dst;
}
struct in6_addr
flow_tnl_src(const struct flow_tnl *tnl)
{
return tnl->ip_src ? in6_addr_mapped_ipv4(tnl->ip_src) : tnl->ipv6_src;
}
/* Parses 's' as a 16-digit hexadecimal number representing a datapath ID. On
* success stores the dpid into '*dpidp' and returns true, on failure stores 0
* into '*dpidp' and returns false.
*
* Rejects an all-zeros dpid as invalid. */
bool
dpid_from_string(const char *s, uint64_t *dpidp)
{
*dpidp = (strlen(s) == 16 && strspn(s, "0123456789abcdefABCDEF") == 16
? strtoull(s, NULL, 16)
: 0);
return *dpidp != 0;
}
/* Returns true if 'ea' is a reserved address, that a bridge must never
* forward, false otherwise.
*
* If you change this function's behavior, please update corresponding
* documentation in vswitch.xml at the same time. */
bool
eth_addr_is_reserved(const struct eth_addr ea)
{
struct eth_addr_node {
struct hmap_node hmap_node;
const uint64_t ea64;
};
static struct eth_addr_node nodes[] = {
/* STP, IEEE pause frames, and other reserved protocols. */
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000000ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000001ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000002ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000003ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000004ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000005ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000006ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000007ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000008ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c2000009ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000aULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000bULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000cULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000dULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000eULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x0180c200000fULL },
/* Extreme protocols. */
{ HMAP_NODE_NULL_INITIALIZER, 0x00e02b000000ULL }, /* EDP. */
{ HMAP_NODE_NULL_INITIALIZER, 0x00e02b000004ULL }, /* EAPS. */
{ HMAP_NODE_NULL_INITIALIZER, 0x00e02b000006ULL }, /* EAPS. */
/* Cisco protocols. */
{ HMAP_NODE_NULL_INITIALIZER, 0x01000c000000ULL }, /* ISL. */
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccccULL }, /* PAgP, UDLD, CDP,
* DTP, VTP. */
{ HMAP_NODE_NULL_INITIALIZER, 0x01000ccccccdULL }, /* PVST+. */
{ HMAP_NODE_NULL_INITIALIZER, 0x01000ccdcdcdULL }, /* STP Uplink Fast,
* FlexLink. */
/* Cisco CFM. */
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc0ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc1ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc2ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc3ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc4ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc5ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc6ULL },
{ HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc7ULL },
};
static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
struct eth_addr_node *node;
static struct hmap addrs;
uint64_t ea64;
if (ovsthread_once_start(&once)) {
hmap_init(&addrs);
for (node = nodes; node < &nodes[ARRAY_SIZE(nodes)]; node++) {
hmap_insert(&addrs, &node->hmap_node, hash_uint64(node->ea64));
}
ovsthread_once_done(&once);
}
ea64 = eth_addr_to_uint64(ea);
HMAP_FOR_EACH_IN_BUCKET (node, hmap_node, hash_uint64(ea64), &addrs) {
if (node->ea64 == ea64) {
return true;
}
}
return false;
}
bool
eth_addr_from_string(const char *s, struct eth_addr *ea)
{
if (ovs_scan(s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(*ea))) {
return true;
} else {
*ea = eth_addr_zero;
return false;
}
}
/* Fills 'b' with a Reverse ARP packet with Ethernet source address 'eth_src'.
* This function is used by Open vSwitch to compose packets in cases where
* context is important but content doesn't (or shouldn't) matter.
*
* The returned packet has enough headroom to insert an 802.1Q VLAN header if
* desired. */
void
compose_rarp(struct dp_packet *b, const struct eth_addr eth_src)
{
struct eth_header *eth;
struct arp_eth_header *arp;
dp_packet_clear(b);
dp_packet_prealloc_tailroom(b, 2 + ETH_HEADER_LEN + VLAN_HEADER_LEN
+ ARP_ETH_HEADER_LEN);
dp_packet_reserve(b, 2 + VLAN_HEADER_LEN);
eth = dp_packet_put_uninit(b, sizeof *eth);
eth->eth_dst = eth_addr_broadcast;
eth->eth_src = eth_src;
eth->eth_type = htons(ETH_TYPE_RARP);
arp = dp_packet_put_uninit(b, sizeof *arp);
arp->ar_hrd = htons(ARP_HRD_ETHERNET);
arp->ar_pro = htons(ARP_PRO_IP);
arp->ar_hln = sizeof arp->ar_sha;
arp->ar_pln = sizeof arp->ar_spa;
arp->ar_op = htons(ARP_OP_RARP);
arp->ar_sha = eth_src;
put_16aligned_be32(&arp->ar_spa, htonl(0));
arp->ar_tha = eth_src;
put_16aligned_be32(&arp->ar_tpa, htonl(0));
dp_packet_reset_offsets(b);
dp_packet_set_l3(b, arp);
}
/* Insert VLAN header according to given TCI. Packet passed must be Ethernet
* packet. Ignores the CFI bit of 'tci' using 0 instead.
*
* Also adjusts the layer offsets accordingly. */
void
eth_push_vlan(struct dp_packet *packet, ovs_be16 tpid, ovs_be16 tci)
{
struct vlan_eth_header *veh;
/* Insert new 802.1Q header. */
veh = dp_packet_resize_l2(packet, VLAN_HEADER_LEN);
memmove(veh, (char *)veh + VLAN_HEADER_LEN, 2 * ETH_ADDR_LEN);
veh->veth_type = tpid;
veh->veth_tci = tci & htons(~VLAN_CFI);
}
/* Removes outermost VLAN header (if any is present) from 'packet'.
*
* 'packet->l2_5' should initially point to 'packet''s outer-most VLAN header
* or may be NULL if there are no VLAN headers. */
void
eth_pop_vlan(struct dp_packet *packet)
{
struct vlan_eth_header *veh = dp_packet_l2(packet);
if (veh && dp_packet_size(packet) >= sizeof *veh
&& eth_type_vlan(veh->veth_type)) {
memmove((char *)veh + VLAN_HEADER_LEN, veh, 2 * ETH_ADDR_LEN);
dp_packet_resize_l2(packet, -VLAN_HEADER_LEN);
}
}
/* Set ethertype of the packet. */
static void
set_ethertype(struct dp_packet *packet, ovs_be16 eth_type)
{
struct eth_header *eh = dp_packet_l2(packet);
if (!eh) {
return;
}
if (eth_type_vlan(eh->eth_type)) {
ovs_be16 *p;
char *l2_5 = dp_packet_l2_5(packet);
p = ALIGNED_CAST(ovs_be16 *,
(l2_5 ? l2_5 : (char *)dp_packet_l3(packet)) - 2);
*p = eth_type;
} else {
eh->eth_type = eth_type;
}
}
static bool is_mpls(struct dp_packet *packet)
{
return packet->l2_5_ofs != UINT16_MAX;
}
/* Set time to live (TTL) of an MPLS label stack entry (LSE). */
void
set_mpls_lse_ttl(ovs_be32 *lse, uint8_t ttl)
{
*lse &= ~htonl(MPLS_TTL_MASK);
*lse |= htonl((ttl << MPLS_TTL_SHIFT) & MPLS_TTL_MASK);
}
/* Set traffic class (TC) of an MPLS label stack entry (LSE). */
void
set_mpls_lse_tc(ovs_be32 *lse, uint8_t tc)
{
*lse &= ~htonl(MPLS_TC_MASK);
*lse |= htonl((tc << MPLS_TC_SHIFT) & MPLS_TC_MASK);
}
/* Set label of an MPLS label stack entry (LSE). */
void
set_mpls_lse_label(ovs_be32 *lse, ovs_be32 label)
{
*lse &= ~htonl(MPLS_LABEL_MASK);
*lse |= htonl((ntohl(label) << MPLS_LABEL_SHIFT) & MPLS_LABEL_MASK);
}
/* Set bottom of stack (BoS) bit of an MPLS label stack entry (LSE). */
void
set_mpls_lse_bos(ovs_be32 *lse, uint8_t bos)
{
*lse &= ~htonl(MPLS_BOS_MASK);
*lse |= htonl((bos << MPLS_BOS_SHIFT) & MPLS_BOS_MASK);
}
/* Compose an MPLS label stack entry (LSE) from its components:
* label, traffic class (TC), time to live (TTL) and
* bottom of stack (BoS) bit. */
ovs_be32
set_mpls_lse_values(uint8_t ttl, uint8_t tc, uint8_t bos, ovs_be32 label)
{
ovs_be32 lse = htonl(0);
set_mpls_lse_ttl(&lse, ttl);
set_mpls_lse_tc(&lse, tc);
set_mpls_lse_bos(&lse, bos);
set_mpls_lse_label(&lse, label);
return lse;
}
/* Set MPLS label stack entry to outermost MPLS header.*/
void
set_mpls_lse(struct dp_packet *packet, ovs_be32 mpls_lse)
{
/* Packet type should be MPLS to set label stack entry. */
if (is_mpls(packet)) {
struct mpls_hdr *mh = dp_packet_l2_5(packet);
/* Update mpls label stack entry. */
put_16aligned_be32(&mh->mpls_lse, mpls_lse);
}
}
/* Push MPLS label stack entry 'lse' onto 'packet' as the outermost MPLS
* header. If 'packet' does not already have any MPLS labels, then its
* Ethertype is changed to 'ethtype' (which must be an MPLS Ethertype). */
void
push_mpls(struct dp_packet *packet, ovs_be16 ethtype, ovs_be32 lse)
{
char * header;
size_t len;
if (!eth_type_mpls(ethtype)) {
return;
}
if (!is_mpls(packet)) {
/* Set MPLS label stack offset. */
packet->l2_5_ofs = packet->l3_ofs;
}
set_ethertype(packet, ethtype);
/* Push new MPLS shim header onto packet. */
len = packet->l2_5_ofs;
header = dp_packet_resize_l2_5(packet, MPLS_HLEN);
memmove(header, header + MPLS_HLEN, len);
memcpy(header + len, &lse, sizeof lse);
}
/* If 'packet' is an MPLS packet, removes its outermost MPLS label stack entry.
* If the label that was removed was the only MPLS label, changes 'packet''s
* Ethertype to 'ethtype' (which ordinarily should not be an MPLS
* Ethertype). */
void
pop_mpls(struct dp_packet *packet, ovs_be16 ethtype)
{
if (is_mpls(packet)) {
struct mpls_hdr *mh = dp_packet_l2_5(packet);
size_t len = packet->l2_5_ofs;
set_ethertype(packet, ethtype);
if (get_16aligned_be32(&mh->mpls_lse) & htonl(MPLS_BOS_MASK)) {
dp_packet_set_l2_5(packet, NULL);
}
/* Shift the l2 header forward. */
memmove((char*)dp_packet_data(packet) + MPLS_HLEN, dp_packet_data(packet), len);
dp_packet_resize_l2_5(packet, -MPLS_HLEN);
}
}
/* Converts hex digits in 'hex' to an Ethernet packet in '*packetp'. The
* caller must free '*packetp'. On success, returns NULL. On failure, returns
* an error message and stores NULL in '*packetp'.
*
* Aligns the L3 header of '*packetp' on a 32-bit boundary. */
const char *
eth_from_hex(const char *hex, struct dp_packet **packetp)
{
struct dp_packet *packet;
/* Use 2 bytes of headroom to 32-bit align the L3 header. */
packet = *packetp = dp_packet_new_with_headroom(strlen(hex) / 2, 2);
if (dp_packet_put_hex(packet, hex, NULL)[0] != '\0') {
dp_packet_delete(packet);
*packetp = NULL;
return "Trailing garbage in packet data";
}
if (dp_packet_size(packet) < ETH_HEADER_LEN) {
dp_packet_delete(packet);
*packetp = NULL;
return "Packet data too short for Ethernet";
}
return NULL;
}
void
eth_format_masked(const struct eth_addr eth,
const struct eth_addr *mask, struct ds *s)
{
ds_put_format(s, ETH_ADDR_FMT, ETH_ADDR_ARGS(eth));
if (mask && !eth_mask_is_exact(*mask)) {
ds_put_format(s, "/"ETH_ADDR_FMT, ETH_ADDR_ARGS(*mask));
}
}
/* Given the IP netmask 'netmask', returns the number of bits of the IP address
* that it specifies, that is, the number of 1-bits in 'netmask'.
*
* If 'netmask' is not a CIDR netmask (see ip_is_cidr()), the return value will
* still be in the valid range but isn't otherwise meaningful. */
int
ip_count_cidr_bits(ovs_be32 netmask)
{
return 32 - ctz32(ntohl(netmask));
}
void
ip_format_masked(ovs_be32 ip, ovs_be32 mask, struct ds *s)
{
ds_put_format(s, IP_FMT, IP_ARGS(ip));
if (mask != OVS_BE32_MAX) {
if (ip_is_cidr(mask)) {
ds_put_format(s, "/%d", ip_count_cidr_bits(mask));
} else {
ds_put_format(s, "/"IP_FMT, IP_ARGS(mask));
}
}
}
/* Parses string 's', which must be an IP address. Stores the IP address into
* '*ip'. Returns true if successful, otherwise false. */
bool
ip_parse(const char *s, ovs_be32 *ip)
{
return inet_pton(AF_INET, s, ip) == 1;
}
/* Parses string 's', which must be an IP address with an optional netmask or
* CIDR prefix length. Stores the IP address into '*ip' and the netmask into
* '*mask'. (If 's' does not contain a netmask, 255.255.255.255 is
* assumed.)
*
* Returns NULL if successful, otherwise an error message that the caller must
* free(). */
char * OVS_WARN_UNUSED_RESULT
ip_parse_masked(const char *s, ovs_be32 *ip, ovs_be32 *mask)
{
int prefix;
int n;
if (ovs_scan(s, IP_SCAN_FMT"/"IP_SCAN_FMT"%n",
IP_SCAN_ARGS(ip), IP_SCAN_ARGS(mask), &n) && !s[n]) {
/* OK. */
} else if (ovs_scan(s, IP_SCAN_FMT"/%d%n", IP_SCAN_ARGS(ip), &prefix, &n)
&& !s[n]) {
if (prefix <= 0 || prefix > 32) {
return xasprintf("%s: network prefix bits not between 0 and "
"32", s);
}
*mask = be32_prefix_mask(prefix);
} else if (ovs_scan(s, IP_SCAN_FMT"%n", IP_SCAN_ARGS(ip), &n) && !s[n]) {
*mask = OVS_BE32_MAX;
} else {
return xasprintf("%s: invalid IP address", s);
}
return NULL;
}
/* Similar to ip_parse_masked(), but the mask, if present, must be a CIDR mask
* and is returned as a prefix length in '*plen'. */
char * OVS_WARN_UNUSED_RESULT
ip_parse_cidr(const char *s, ovs_be32 *ip, unsigned int *plen)
{
ovs_be32 mask;
char *error;
error = ip_parse_masked(s, ip, &mask);
if (error) {
return error;
}
if (!ip_is_cidr(mask)) {
return xasprintf("%s: CIDR network required", s);
}
*plen = ip_count_cidr_bits(mask);
return NULL;
}
/* Parses string 's', which must be an IPv6 address. Stores the IPv6 address
* into '*ip'. Returns true if successful, otherwise false. */
bool
ipv6_parse(const char *s, struct in6_addr *ip)
{
return inet_pton(AF_INET6, s, ip) == 1;
}
/* Parses string 's', which must be an IPv6 address with an optional netmask or
* CIDR prefix length. Stores the IPv6 address into '*ip' and the netmask into
* '*mask'. (If 's' does not contain a netmask, all-one-bits is assumed.)
*
* Returns NULL if successful, otherwise an error message that the caller must
* free(). */
char * OVS_WARN_UNUSED_RESULT
ipv6_parse_masked(const char *s, struct in6_addr *ip, struct in6_addr *mask)
{
char ipv6_s[IPV6_SCAN_LEN + 1];
int prefix;
int n;
if (ovs_scan(s, IPV6_SCAN_FMT"%n", ipv6_s, &n) && ipv6_parse(ipv6_s, ip)) {
s += n;
if (!*s) {
*mask = in6addr_exact;
} else if (ovs_scan(s, "/%d%n", &prefix, &n) && !s[n]) {
if (prefix <= 0 || prefix > 128) {
return xasprintf("%s: IPv6 network prefix bits not between 0 "
"and 128", s);
}
*mask = ipv6_create_mask(prefix);
} else if (ovs_scan(s, "/"IPV6_SCAN_FMT"%n", ipv6_s, &n)
&& !s[n]
&& ipv6_parse(ipv6_s, mask)) {
/* OK. */
} else {
return xasprintf("%s: syntax error expecting IPv6 prefix length "
"or mask", s);
}
return NULL;
}
return xasprintf("%s: invalid IPv6 address", s);
}
/* Similar to ipv6_parse_masked(), but the mask, if present, must be a CIDR
* mask and is returned as a prefix length in '*plen'. */
char * OVS_WARN_UNUSED_RESULT
ipv6_parse_cidr(const char *s, struct in6_addr *ip, unsigned int *plen)
{
struct in6_addr mask;
char *error;
error = ipv6_parse_masked(s, ip, &mask);
if (error) {
return error;
}
if (!ipv6_is_cidr(&mask)) {
return xasprintf("%s: IPv6 CIDR network required", s);
}
*plen = ipv6_count_cidr_bits(&mask);
return NULL;
}
/* Stores the string representation of the IPv6 address 'addr' into the
* character array 'addr_str', which must be at least INET6_ADDRSTRLEN
* bytes long. */
void
ipv6_format_addr(const struct in6_addr *addr, struct ds *s)
{
char *dst;
ds_reserve(s, s->length + INET6_ADDRSTRLEN);
dst = s->string + s->length;
inet_ntop(AF_INET6, addr, dst, INET6_ADDRSTRLEN);
s->length += strlen(dst);
}
/* Same as print_ipv6_addr, but optionally encloses the address in square
* brackets. */
void
ipv6_format_addr_bracket(const struct in6_addr *addr, struct ds *s,
bool bracket)
{
if (bracket) {
ds_put_char(s, '[');
}
ipv6_format_addr(addr, s);
if (bracket) {
ds_put_char(s, ']');
}
}
void
ipv6_format_mapped(const struct in6_addr *addr, struct ds *s)
{
if (IN6_IS_ADDR_V4MAPPED(addr)) {
ds_put_format(s, IP_FMT, addr->s6_addr[12], addr->s6_addr[13],
addr->s6_addr[14], addr->s6_addr[15]);
} else {
ipv6_format_addr(addr, s);
}
}
void
ipv6_format_masked(const struct in6_addr *addr, const struct in6_addr *mask,
struct ds *s)
{
ipv6_format_addr(addr, s);
if (mask && !ipv6_mask_is_exact(mask)) {
if (ipv6_is_cidr(mask)) {
int cidr_bits = ipv6_count_cidr_bits(mask);
ds_put_format(s, "/%d", cidr_bits);
} else {
ds_put_char(s, '/');
ipv6_format_addr(mask, s);
}
}
}
/* Stores the string representation of the IPv6 address 'addr' into the
* character array 'addr_str', which must be at least INET6_ADDRSTRLEN
* bytes long. If addr is IPv4-mapped, store an IPv4 dotted-decimal string. */
const char *
ipv6_string_mapped(char *addr_str, const struct in6_addr *addr)
{
ovs_be32 ip;
ip = in6_addr_get_mapped_ipv4(addr);
if (ip) {
return inet_ntop(AF_INET, &ip, addr_str, INET6_ADDRSTRLEN);
} else {
return inet_ntop(AF_INET6, addr, addr_str, INET6_ADDRSTRLEN);
}
}
struct in6_addr ipv6_addr_bitand(const struct in6_addr *a,
const struct in6_addr *b)
{
int i;
struct in6_addr dst;
#ifdef s6_addr32
for (i=0; i<4; i++) {
dst.s6_addr32[i] = a->s6_addr32[i] & b->s6_addr32[i];
}
#else
for (i=0; i<16; i++) {
dst.s6_addr[i] = a->s6_addr[i] & b->s6_addr[i];
}
#endif
return dst;
}
/* Returns an in6_addr consisting of 'mask' high-order 1-bits and 128-N
* low-order 0-bits. */
struct in6_addr
ipv6_create_mask(int mask)
{
struct in6_addr netmask;
uint8_t *netmaskp = &netmask.s6_addr[0];
memset(&netmask, 0, sizeof netmask);
while (mask > 8) {
*netmaskp = 0xff;
netmaskp++;
mask -= 8;
}
if (mask) {
*netmaskp = 0xff << (8 - mask);
}
return netmask;
}
/* Given the IPv6 netmask 'netmask', returns the number of bits of the IPv6
* address that it specifies, that is, the number of 1-bits in 'netmask'.
* 'netmask' must be a CIDR netmask (see ipv6_is_cidr()).
*
* If 'netmask' is not a CIDR netmask (see ipv6_is_cidr()), the return value
* will still be in the valid range but isn't otherwise meaningful. */
int
ipv6_count_cidr_bits(const struct in6_addr *netmask)
{
int i;
int count = 0;
const uint8_t *netmaskp = &netmask->s6_addr[0];
for (i=0; i<16; i++) {
if (netmaskp[i] == 0xff) {
count += 8;
} else {
uint8_t nm;
for(nm = netmaskp[i]; nm; nm <<= 1) {
count++;
}
break;
}
}
return count;
}
/* Returns true if 'netmask' is a CIDR netmask, that is, if it consists of N
* high-order 1-bits and 128-N low-order 0-bits. */
bool
ipv6_is_cidr(const struct in6_addr *netmask)
{
const uint8_t *netmaskp = &netmask->s6_addr[0];
int i;
for (i=0; i<16; i++) {
if (netmaskp[i] != 0xff) {
uint8_t x = ~netmaskp[i];
if (x & (x + 1)) {
return false;
}
while (++i < 16) {
if (netmaskp[i]) {
return false;
}
}
}
}
return true;
}
/* Populates 'b' with an Ethernet II packet headed with the given 'eth_dst',
* 'eth_src' and 'eth_type' parameters. A payload of 'size' bytes is allocated
* in 'b' and returned. This payload may be populated with appropriate
* information by the caller. Sets 'b''s 'frame' pointer and 'l3' offset to
* the Ethernet header and payload respectively. Aligns b->l3 on a 32-bit
* boundary.
*
* The returned packet has enough headroom to insert an 802.1Q VLAN header if
* desired. */
void *
eth_compose(struct dp_packet *b, const struct eth_addr eth_dst,
const struct eth_addr eth_src, uint16_t eth_type,
size_t size)
{
void *data;
struct eth_header *eth;
dp_packet_clear(b);
/* The magic 2 here ensures that the L3 header (when it is added later)
* will be 32-bit aligned. */
dp_packet_prealloc_tailroom(b, 2 + ETH_HEADER_LEN + VLAN_HEADER_LEN + size);
dp_packet_reserve(b, 2 + VLAN_HEADER_LEN);
eth = dp_packet_put_uninit(b, ETH_HEADER_LEN);
data = dp_packet_put_uninit(b, size);
eth->eth_dst = eth_dst;
eth->eth_src = eth_src;
eth->eth_type = htons(eth_type);
dp_packet_reset_offsets(b);
dp_packet_set_l3(b, data);
return data;
}
static void
packet_set_ipv4_addr(struct dp_packet *packet,
ovs_16aligned_be32 *addr, ovs_be32 new_addr)
{
struct ip_header *nh = dp_packet_l3(packet);
ovs_be32 old_addr = get_16aligned_be32(addr);
size_t l4_size = dp_packet_l4_size(packet);
if (nh->ip_proto == IPPROTO_TCP && l4_size >= TCP_HEADER_LEN) {
struct tcp_header *th = dp_packet_l4(packet);
th->tcp_csum = recalc_csum32(th->tcp_csum, old_addr, new_addr);
} else if (nh->ip_proto == IPPROTO_UDP && l4_size >= UDP_HEADER_LEN ) {
struct udp_header *uh = dp_packet_l4(packet);
if (uh->udp_csum) {
uh->udp_csum = recalc_csum32(uh->udp_csum, old_addr, new_addr);
if (!uh->udp_csum) {
uh->udp_csum = htons(0xffff);
}
}
}
nh->ip_csum = recalc_csum32(nh->ip_csum, old_addr, new_addr);
put_16aligned_be32(addr, new_addr);
}
/* Returns true, if packet contains at least one routing header where
* segements_left > 0.
*
* This function assumes that L3 and L4 offsets are set in the packet. */
static bool
packet_rh_present(struct dp_packet *packet)
{
const struct ovs_16aligned_ip6_hdr *nh;
int nexthdr;
size_t len;
size_t remaining;
uint8_t *data = dp_packet_l3(packet);
remaining = packet->l4_ofs - packet->l3_ofs;
if (remaining < sizeof *nh) {
return false;
}
nh = ALIGNED_CAST(struct ovs_16aligned_ip6_hdr *, data);
data += sizeof *nh;
remaining -= sizeof *nh;
nexthdr = nh->ip6_nxt;
while (1) {
if ((nexthdr != IPPROTO_HOPOPTS)
&& (nexthdr != IPPROTO_ROUTING)
&& (nexthdr != IPPROTO_DSTOPTS)
&& (nexthdr != IPPROTO_AH)
&& (nexthdr != IPPROTO_FRAGMENT)) {
/* It's either a terminal header (e.g., TCP, UDP) or one we
* don't understand. In either case, we're done with the
* packet, so use it to fill in 'nw_proto'. */
break;
}
/* We only verify that at least 8 bytes of the next header are
* available, but many of these headers are longer. Ensure that
* accesses within the extension header are within those first 8
* bytes. All extension headers are required to be at least 8
* bytes. */
if (remaining < 8) {
return false;
}
if (nexthdr == IPPROTO_AH) {
/* A standard AH definition isn't available, but the fields
* we care about are in the same location as the generic
* option header--only the header length is calculated
* differently. */
const struct ip6_ext *ext_hdr = (struct ip6_ext *)data;
nexthdr = ext_hdr->ip6e_nxt;
len = (ext_hdr->ip6e_len + 2) * 4;
} else if (nexthdr == IPPROTO_FRAGMENT) {
const struct ovs_16aligned_ip6_frag *frag_hdr
= ALIGNED_CAST(struct ovs_16aligned_ip6_frag *, data);
nexthdr = frag_hdr->ip6f_nxt;
len = sizeof *frag_hdr;
} else if (nexthdr == IPPROTO_ROUTING) {
const struct ip6_rthdr *rh = (struct ip6_rthdr *)data;
if (rh->ip6r_segleft > 0) {
return true;
}
nexthdr = rh->ip6r_nxt;
len = (rh->ip6r_len + 1) * 8;
} else {
const struct ip6_ext *ext_hdr = (struct ip6_ext *)data;
nexthdr = ext_hdr->ip6e_nxt;
len = (ext_hdr->ip6e_len + 1) * 8;
}
if (remaining < len) {
return false;
}
remaining -= len;
data += len;
}
return false;
}
static void
packet_update_csum128(struct dp_packet *packet, uint8_t proto,
ovs_16aligned_be32 addr[4], const ovs_be32 new_addr[4])
{
size_t l4_size = dp_packet_l4_size(packet);
if (proto == IPPROTO_TCP && l4_size >= TCP_HEADER_LEN) {
struct tcp_header *th = dp_packet_l4(packet);
th->tcp_csum = recalc_csum128(th->tcp_csum, addr, new_addr);
} else if (proto == IPPROTO_UDP && l4_size >= UDP_HEADER_LEN) {
struct udp_header *uh = dp_packet_l4(packet);
if (uh->udp_csum) {
uh->udp_csum = recalc_csum128(uh->udp_csum, addr, new_addr);
if (!uh->udp_csum) {
uh->udp_csum = htons(0xffff);
}
}
} else if (proto == IPPROTO_ICMPV6 &&
l4_size >= sizeof(struct icmp6_header)) {
struct icmp6_header *icmp = dp_packet_l4(packet);
icmp->icmp6_cksum = recalc_csum128(icmp->icmp6_cksum, addr, new_addr);
}
}
static void
packet_set_ipv6_addr(struct dp_packet *packet, uint8_t proto,
ovs_16aligned_be32 addr[4], const ovs_be32 new_addr[4],
bool recalculate_csum)
{
if (recalculate_csum) {
packet_update_csum128(packet, proto, addr, new_addr);
}
memcpy(addr, new_addr, sizeof(ovs_be32[4]));
}
static void
packet_set_ipv6_flow_label(ovs_16aligned_be32 *flow_label, ovs_be32 flow_key)
{
ovs_be32 old_label = get_16aligned_be32(flow_label);
ovs_be32 new_label = (old_label & htonl(~IPV6_LABEL_MASK)) | flow_key;
put_16aligned_be32(flow_label, new_label);
}
static void
packet_set_ipv6_tc(ovs_16aligned_be32 *flow_label, uint8_t tc)
{
ovs_be32 old_label = get_16aligned_be32(flow_label);
ovs_be32 new_label = (old_label & htonl(0xF00FFFFF)) | htonl(tc << 20);
put_16aligned_be32(flow_label, new_label);
}
/* Modifies the IPv4 header fields of 'packet' to be consistent with 'src',
* 'dst', 'tos', and 'ttl'. Updates 'packet''s L4 checksums as appropriate.
* 'packet' must contain a valid IPv4 packet with correctly populated l[347]
* markers. */
void
packet_set_ipv4(struct dp_packet *packet, ovs_be32 src, ovs_be32 dst,
uint8_t tos, uint8_t ttl)
{
struct ip_header *nh = dp_packet_l3(packet);
if (get_16aligned_be32(&nh->ip_src) != src) {
packet_set_ipv4_addr(packet, &nh->ip_src, src);
}
if (get_16aligned_be32(&nh->ip_dst) != dst) {
packet_set_ipv4_addr(packet, &nh->ip_dst, dst);
}
if (nh->ip_tos != tos) {
uint8_t *field = &nh->ip_tos;
nh->ip_csum = recalc_csum16(nh->ip_csum, htons((uint16_t) *field),
htons((uint16_t) tos));
*field = tos;
}
if (nh->ip_ttl != ttl) {
uint8_t *field = &nh->ip_ttl;
nh->ip_csum = recalc_csum16(nh->ip_csum, htons(*field << 8),
htons(ttl << 8));
*field = ttl;
}
}
/* Modifies the IPv6 header fields of 'packet' to be consistent with 'src',
* 'dst', 'traffic class', and 'next hop'. Updates 'packet''s L4 checksums as
* appropriate. 'packet' must contain a valid IPv6 packet with correctly
* populated l[34] offsets. */
void
packet_set_ipv6(struct dp_packet *packet, uint8_t proto, const ovs_be32 src[4],
const ovs_be32 dst[4], uint8_t key_tc, ovs_be32 key_fl,
uint8_t key_hl)
{
struct ovs_16aligned_ip6_hdr *nh = dp_packet_l3(packet);
if (memcmp(&nh->ip6_src, src, sizeof(ovs_be32[4]))) {
packet_set_ipv6_addr(packet, proto, nh->ip6_src.be32, src, true);
}
if (memcmp(&nh->ip6_dst, dst, sizeof(ovs_be32[4]))) {
packet_set_ipv6_addr(packet, proto, nh->ip6_dst.be32, dst,
!packet_rh_present(packet));
}
packet_set_ipv6_tc(&nh->ip6_flow, key_tc);
packet_set_ipv6_flow_label(&nh->ip6_flow, key_fl);
nh->ip6_hlim = key_hl;
}
static void
packet_set_port(ovs_be16 *port, ovs_be16 new_port, ovs_be16 *csum)
{
if (*port != new_port) {
*csum = recalc_csum16(*csum, *port, new_port);
*port = new_port;
}
}
/* Sets the TCP source and destination port ('src' and 'dst' respectively) of
* the TCP header contained in 'packet'. 'packet' must be a valid TCP packet
* with its l4 offset properly populated. */
void
packet_set_tcp_port(struct dp_packet *packet, ovs_be16 src, ovs_be16 dst)
{
struct tcp_header *th = dp_packet_l4(packet);
packet_set_port(&th->tcp_src, src, &th->tcp_csum);
packet_set_port(&th->tcp_dst, dst, &th->tcp_csum);
}
/* Sets the UDP source and destination port ('src' and 'dst' respectively) of
* the UDP header contained in 'packet'. 'packet' must be a valid UDP packet
* with its l4 offset properly populated. */
void
packet_set_udp_port(struct dp_packet *packet, ovs_be16 src, ovs_be16 dst)
{
struct udp_header *uh = dp_packet_l4(packet);
if (uh->udp_csum) {
packet_set_port(&uh->udp_src, src, &uh->udp_csum);
packet_set_port(&uh->udp_dst, dst, &uh->udp_csum);
if (!uh->udp_csum) {
uh->udp_csum = htons(0xffff);
}
} else {
uh->udp_src = src;
uh->udp_dst = dst;
}
}
/* Sets the SCTP source and destination port ('src' and 'dst' respectively) of
* the SCTP header contained in 'packet'. 'packet' must be a valid SCTP packet
* with its l4 offset properly populated. */
void
packet_set_sctp_port(struct dp_packet *packet, ovs_be16 src, ovs_be16 dst)
{
struct sctp_header *sh = dp_packet_l4(packet);
ovs_be32 old_csum, old_correct_csum, new_csum;
uint16_t tp_len = dp_packet_l4_size(packet);
old_csum = get_16aligned_be32(&sh->sctp_csum);
put_16aligned_be32(&sh->sctp_csum, 0);
old_correct_csum = crc32c((void *)sh, tp_len);
sh->sctp_src = src;
sh->sctp_dst = dst;
new_csum = crc32c((void *)sh, tp_len);
put_16aligned_be32(&sh->sctp_csum, old_csum ^ old_correct_csum ^ new_csum);
}
/* Sets the ICMP type and code of the ICMP header contained in 'packet'.
* 'packet' must be a valid ICMP packet with its l4 offset properly
* populated. */
void
packet_set_icmp(struct dp_packet *packet, uint8_t type, uint8_t code)
{
struct icmp_header *ih = dp_packet_l4(packet);
ovs_be16 orig_tc = htons(ih->icmp_type << 8 | ih->icmp_code);
ovs_be16 new_tc = htons(type << 8 | code);
if (orig_tc != new_tc) {
ih->icmp_type = type;
ih->icmp_code = code;
ih->icmp_csum = recalc_csum16(ih->icmp_csum, orig_tc, new_tc);
}
}
void
packet_set_nd(struct dp_packet *packet, const ovs_be32 target[4],
const struct eth_addr sll, const struct eth_addr tll) {
struct ovs_nd_msg *ns;
struct ovs_nd_opt *nd_opt;
int bytes_remain = dp_packet_l4_size(packet);
if (OVS_UNLIKELY(bytes_remain < sizeof(*ns))) {
return;
}
ns = dp_packet_l4(packet);
nd_opt = &ns->options[0];
bytes_remain -= sizeof(*ns);
if (memcmp(&ns->target, target, sizeof(ovs_be32[4]))) {
packet_set_ipv6_addr(packet, IPPROTO_ICMPV6,
ns->target.be32,
target, true);
}
while (bytes_remain >= ND_OPT_LEN && nd_opt->nd_opt_len != 0) {
if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LINKADDR
&& nd_opt->nd_opt_len == 1) {
if (!eth_addr_equals(nd_opt->nd_opt_mac, sll)) {
ovs_be16 *csum = &(ns->icmph.icmp6_cksum);
*csum = recalc_csum48(*csum, nd_opt->nd_opt_mac, sll);
nd_opt->nd_opt_mac = sll;
}
/* A packet can only contain one SLL or TLL option */
break;
} else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LINKADDR
&& nd_opt->nd_opt_len == 1) {
if (!eth_addr_equals(nd_opt->nd_opt_mac, tll)) {
ovs_be16 *csum = &(ns->icmph.icmp6_cksum);
*csum = recalc_csum48(*csum, nd_opt->nd_opt_mac, tll);
nd_opt->nd_opt_mac = tll;
}
/* A packet can only contain one SLL or TLL option */
break;
}
nd_opt += nd_opt->nd_opt_len;
bytes_remain -= nd_opt->nd_opt_len * ND_OPT_LEN;
}
}
const char *
packet_tcp_flag_to_string(uint32_t flag)
{
switch (flag) {
case TCP_FIN:
return "fin";
case TCP_SYN:
return "syn";
case TCP_RST:
return "rst";
case TCP_PSH:
return "psh";
case TCP_ACK:
return "ack";
case TCP_URG:
return "urg";
case TCP_ECE:
return "ece";
case TCP_CWR:
return "cwr";
case TCP_NS:
return "ns";
case 0x200:
return "[200]";
case 0x400:
return "[400]";
case 0x800:
return "[800]";
default:
return NULL;
}
}
/* Appends a string representation of the TCP flags value 'tcp_flags'
* (e.g. from struct flow.tcp_flags or obtained via TCP_FLAGS) to 's', in the
* format used by tcpdump. */
void
packet_format_tcp_flags(struct ds *s, uint16_t tcp_flags)
{
if (!tcp_flags) {
ds_put_cstr(s, "none");
return;
}
if (tcp_flags & TCP_SYN) {
ds_put_char(s, 'S');
}
if (tcp_flags & TCP_FIN) {
ds_put_char(s, 'F');
}
if (tcp_flags & TCP_PSH) {
ds_put_char(s, 'P');
}
if (tcp_flags & TCP_RST) {
ds_put_char(s, 'R');
}
if (tcp_flags & TCP_URG) {
ds_put_char(s, 'U');
}
if (tcp_flags & TCP_ACK) {
ds_put_char(s, '.');
}
if (tcp_flags & TCP_ECE) {
ds_put_cstr(s, "E");
}
if (tcp_flags & TCP_CWR) {
ds_put_cstr(s, "C");
}
if (tcp_flags & TCP_NS) {
ds_put_cstr(s, "N");
}
if (tcp_flags & 0x200) {
ds_put_cstr(s, "[200]");
}
if (tcp_flags & 0x400) {
ds_put_cstr(s, "[400]");
}
if (tcp_flags & 0x800) {
ds_put_cstr(s, "[800]");
}
}
#define ARP_PACKET_SIZE (2 + ETH_HEADER_LEN + VLAN_HEADER_LEN + \
ARP_ETH_HEADER_LEN)
/* Clears 'b' and replaces its contents by an ARP frame with the specified
* 'arp_op', 'arp_sha', 'arp_tha', 'arp_spa', and 'arp_tpa'. The outer
* Ethernet frame is initialized with Ethernet source 'arp_sha' and destination
* 'arp_tha', except that destination ff:ff:ff:ff:ff:ff is used instead if
* 'broadcast' is true. */
void
compose_arp(struct dp_packet *b, uint16_t arp_op,
const struct eth_addr arp_sha, const struct eth_addr arp_tha,
bool broadcast, ovs_be32 arp_spa, ovs_be32 arp_tpa)
{
struct eth_header *eth;
struct arp_eth_header *arp;
dp_packet_clear(b);
dp_packet_prealloc_tailroom(b, ARP_PACKET_SIZE);
dp_packet_reserve(b, 2 + VLAN_HEADER_LEN);
eth = dp_packet_put_uninit(b, sizeof *eth);
eth->eth_dst = broadcast ? eth_addr_broadcast : arp_tha;
eth->eth_src = arp_sha;
eth->eth_type = htons(ETH_TYPE_ARP);
arp = dp_packet_put_uninit(b, sizeof *arp);
arp->ar_hrd = htons(ARP_HRD_ETHERNET);
arp->ar_pro = htons(ARP_PRO_IP);
arp->ar_hln = sizeof arp->ar_sha;
arp->ar_pln = sizeof arp->ar_spa;
arp->ar_op = htons(arp_op);
arp->ar_sha = arp_sha;
arp->ar_tha = arp_tha;
put_16aligned_be32(&arp->ar_spa, arp_spa);
put_16aligned_be32(&arp->ar_tpa, arp_tpa);
dp_packet_reset_offsets(b);
dp_packet_set_l3(b, arp);
}
void
compose_nd(struct dp_packet *b, const struct eth_addr eth_src,
struct in6_addr * ipv6_src, struct in6_addr * ipv6_dst)
{
struct in6_addr sn_addr;
struct eth_addr eth_dst;
struct ovs_nd_msg *ns;
struct ovs_nd_opt *nd_opt;
in6_addr_solicited_node(&sn_addr, ipv6_dst);
ipv6_multicast_to_ethernet(&eth_dst, &sn_addr);
eth_compose(b, eth_dst, eth_src, ETH_TYPE_IPV6,
IPV6_HEADER_LEN + ICMP6_HEADER_LEN + ND_OPT_LEN);
packet_set_ipv6(b, IPPROTO_ICMPV6,
ALIGNED_CAST(ovs_be32 *, ipv6_src->s6_addr),
ALIGNED_CAST(ovs_be32 *, sn_addr.s6_addr),
0, 0, 255);
ns = dp_packet_l4(b);
nd_opt = &ns->options[0];
ns->icmph.icmp6_type = ND_NEIGHBOR_SOLICIT;
ns->icmph.icmp6_code = 0;
nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
packet_set_nd(b, ALIGNED_CAST(ovs_be32 *, ipv6_dst->s6_addr),
eth_src, eth_addr_zero);
}
uint32_t
packet_csum_pseudoheader(const struct ip_header *ip)
{
uint32_t partial = 0;
partial = csum_add32(partial, get_16aligned_be32(&ip->ip_src));
partial = csum_add32(partial, get_16aligned_be32(&ip->ip_dst));
partial = csum_add16(partial, htons(ip->ip_proto));
partial = csum_add16(partial, htons(ntohs(ip->ip_tot_len) -
IP_IHL(ip->ip_ihl_ver) * 4));
return partial;
}
#ifndef __CHECKER__
uint32_t
packet_csum_pseudoheader6(const struct ovs_16aligned_ip6_hdr *ip6)
{
uint32_t partial = 0;
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_src.be32[0])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_src.be32[1])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_src.be32[2])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_src.be32[3])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_dst.be32[0])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_dst.be32[1])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_dst.be32[2])));
partial = csum_add32(partial, get_16aligned_be32(&(ip6->ip6_dst.be32[3])));
partial = csum_add16(partial, 0);
partial = csum_add16(partial, ip6->ip6_plen);
partial = csum_add16(partial, 0);
partial = csum_add16(partial, ip6->ip6_nxt);
return partial;
}
#endif
Reference in New Issue View Git Blame Copy Permalink