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ovs/lib/packets.c
Jesse Gross 0292a0c9d9 packet: Add IP pseudoheader checksum calculation. 
As OVS adds userspace support for being the endpoint in protocols
like tunnels, it will need to be able to calculate pseudoheaders
as part of the checksum calculation.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
2015-04-07 16:51:57 -07:00

1060 lines
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/*
* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 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;
/* 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 uint8_t ea[ETH_ADDR_LEN])
{
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, uint8_t ea[ETH_ADDR_LEN])
{
if (ovs_scan(s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(ea))) {
return true;
} else {
memset(ea, 0, ETH_ADDR_LEN);
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 uint8_t eth_src[ETH_ADDR_LEN])
{
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);
memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
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);
memcpy(arp->ar_sha, eth_src, ETH_ADDR_LEN);
put_16aligned_be32(&arp->ar_spa, htonl(0));
memcpy(arp->ar_tha, eth_src, ETH_ADDR_LEN);
put_16aligned_be32(&arp->ar_tpa, htonl(0));
dp_packet_set_frame(b, eth);
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 MPLS header
* or may be NULL if there are no MPLS 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
&& veh->veth_type == htons(ETH_TYPE_VLAN)) {
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 (eh->eth_type == htons(ETH_TYPE_VLAN)) {
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 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 uint8_t eth[ETH_ADDR_LEN],
const uint8_t mask[ETH_ADDR_LEN], 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));
}
}
void
eth_addr_bitand(const uint8_t src[ETH_ADDR_LEN],
const uint8_t mask[ETH_ADDR_LEN],
uint8_t dst[ETH_ADDR_LEN])
{
int i;
for (i = 0; i < ETH_ADDR_LEN; i++) {
dst[i] = src[i] & mask[i];
}
}
/* 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));
}
}
}
/* 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
format_ipv6_addr(char *addr_str, const struct in6_addr *addr)
{
inet_ntop(AF_INET6, addr, addr_str, INET6_ADDRSTRLEN);
}
void
print_ipv6_addr(struct ds *string, const struct in6_addr *addr)
{
char *dst;
ds_reserve(string, string->length + INET6_ADDRSTRLEN);
dst = string->string + string->length;
format_ipv6_addr(dst, addr);
string->length += strlen(dst);
}
void
print_ipv6_masked(struct ds *s, const struct in6_addr *addr,
const struct in6_addr *mask)
{
print_ipv6_addr(s, addr);
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, '/');
print_ipv6_addr(s, mask);
}
}
}
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 uint8_t eth_dst[ETH_ADDR_LEN],
const uint8_t eth_src[ETH_ADDR_LEN], 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);
memcpy(eth->eth_dst, eth_dst, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
eth->eth_type = htons(eth_type);
dp_packet_set_frame(b, eth);
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);
}
void
packet_set_nd(struct dp_packet *packet, const ovs_be32 target[4],
const uint8_t sll[ETH_ADDR_LEN],
const uint8_t tll[ETH_ADDR_LEN]) {
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 (memcmp(nd_opt->nd_opt_data, sll, ETH_ADDR_LEN)) {
ovs_be16 *csum = &(ns->icmph.icmp6_cksum);
*csum = recalc_csum48(*csum, nd_opt->nd_opt_data, sll);
memcpy(nd_opt->nd_opt_data, sll, ETH_ADDR_LEN);
}
/* 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 (memcmp(nd_opt->nd_opt_data, tll, ETH_ADDR_LEN)) {
ovs_be16 *csum = &(ns->icmph.icmp6_cksum);
*csum = recalc_csum48(*csum, nd_opt->nd_opt_data, tll);
memcpy(nd_opt->nd_opt_data, tll, ETH_ADDR_LEN);
}
/* 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)
void
compose_arp(struct dp_packet *b, const uint8_t eth_src[ETH_ADDR_LEN],
ovs_be32 ip_src, ovs_be32 ip_dst)
{
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);
memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
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_REQUEST);
memcpy(arp->ar_sha, eth_src, ETH_ADDR_LEN);
memset(arp->ar_tha, 0, ETH_ADDR_LEN);
put_16aligned_be32(&arp->ar_spa, ip_src);
put_16aligned_be32(&arp->ar_tpa, ip_dst);
dp_packet_set_frame(b, eth);
dp_packet_set_l3(b, arp);
}
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;
}
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