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qemu/net/eth.c
Thomas Jansen 9d6267b240 net/eth: Don't consider ESP to be an IPv6 option header 
The IPv6 option headers all have in common that they start with some
common fields, in particular the type of the next header followed by the
extention header length. This is used to traverse the list of the
options. The ESP header does not follow that format, which can break the
IPv6 option header traversal code in eth_parse_ipv6_hdr().

The effect of that is that network interfaces such as vmxnet3 that use
the following call chain
  eth_is_ip6_extension_header_type
  eth_parse_ipv6_hdr
  net_tx_pkt_parse_headers
  net_tx_pkt_parse
  vmxnet3_process_tx_queue
to send packets from the VM out to the host will drop packets of the
following structure:
  Ethernet-Header(IPv6-Header(ESP(encrypted data)))

Note that not all types of network interfaces use the net_tx_pkt_parse
function though, leading to inconsistent behavior regarding sending
those packets. The e1000 network interface for example does not suffer
from this limitation.

By not considering ESP to be an IPv6 header we can allow sending those
packets out to the host on all types of network interfaces.

Fixes: 75020a7021 ("Common definitions for VMWARE devices")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/149
Buglink: https://bugs.launchpad.net/qemu/+bug/1758091
Signed-off-by: Thomas Jansen <mithi@mithi.net>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2022-02-14 11:50:44 +08:00

567 lines
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/*
* QEMU network structures definitions and helper functions
*
* Copyright (c) 2012 Ravello Systems LTD (http://ravellosystems.com)
*
* Developed by Daynix Computing LTD (http://www.daynix.com)
*
* Authors:
* Dmitry Fleytman <dmitry@daynix.com>
* Tamir Shomer <tamirs@daynix.com>
* Yan Vugenfirer <yan@daynix.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "net/eth.h"
#include "net/checksum.h"
#include "net/tap.h"
void eth_setup_vlan_headers_ex(struct eth_header *ehdr, uint16_t vlan_tag,
uint16_t vlan_ethtype, bool *is_new)
{
struct vlan_header *vhdr = PKT_GET_VLAN_HDR(ehdr);
switch (be16_to_cpu(ehdr->h_proto)) {
case ETH_P_VLAN:
case ETH_P_DVLAN:
/* vlan hdr exists */
*is_new = false;
break;
default:
/* No VLAN header, put a new one */
vhdr->h_proto = ehdr->h_proto;
ehdr->h_proto = cpu_to_be16(vlan_ethtype);
*is_new = true;
break;
}
vhdr->h_tci = cpu_to_be16(vlan_tag);
}
uint8_t
eth_get_gso_type(uint16_t l3_proto, uint8_t *l3_hdr, uint8_t l4proto)
{
uint8_t ecn_state = 0;
if (l3_proto == ETH_P_IP) {
struct ip_header *iphdr = (struct ip_header *) l3_hdr;
if (IP_HEADER_VERSION(iphdr) == IP_HEADER_VERSION_4) {
if (IPTOS_ECN(iphdr->ip_tos) == IPTOS_ECN_CE) {
ecn_state = VIRTIO_NET_HDR_GSO_ECN;
}
if (l4proto == IP_PROTO_TCP) {
return VIRTIO_NET_HDR_GSO_TCPV4 | ecn_state;
} else if (l4proto == IP_PROTO_UDP) {
return VIRTIO_NET_HDR_GSO_UDP | ecn_state;
}
}
} else if (l3_proto == ETH_P_IPV6) {
struct ip6_header *ip6hdr = (struct ip6_header *) l3_hdr;
if (IP6_ECN(ip6hdr->ip6_ecn_acc) == IP6_ECN_CE) {
ecn_state = VIRTIO_NET_HDR_GSO_ECN;
}
if (l4proto == IP_PROTO_TCP) {
return VIRTIO_NET_HDR_GSO_TCPV6 | ecn_state;
}
}
qemu_log_mask(LOG_UNIMP, "%s: probably not GSO frame, "
"unknown L3 protocol: 0x%04"PRIx16"\n", __func__, l3_proto);
return VIRTIO_NET_HDR_GSO_NONE | ecn_state;
}
uint16_t
eth_get_l3_proto(const struct iovec *l2hdr_iov, int iovcnt, size_t l2hdr_len)
{
uint16_t proto;
size_t copied;
size_t size = iov_size(l2hdr_iov, iovcnt);
size_t proto_offset = l2hdr_len - sizeof(proto);
if (size < proto_offset) {
return ETH_P_UNKNOWN;
}
copied = iov_to_buf(l2hdr_iov, iovcnt, proto_offset,
&proto, sizeof(proto));
return (copied == sizeof(proto)) ? be16_to_cpu(proto) : ETH_P_UNKNOWN;
}
static bool
_eth_copy_chunk(size_t input_size,
const struct iovec *iov, int iovcnt,
size_t offset, size_t length,
void *buffer)
{
size_t copied;
if (input_size < offset) {
return false;
}
copied = iov_to_buf(iov, iovcnt, offset, buffer, length);
if (copied < length) {
return false;
}
return true;
}
static bool
_eth_tcp_has_data(bool is_ip4,
const struct ip_header *ip4_hdr,
const struct ip6_header *ip6_hdr,
size_t full_ip6hdr_len,
const struct tcp_header *tcp)
{
uint32_t l4len;
if (is_ip4) {
l4len = be16_to_cpu(ip4_hdr->ip_len) - IP_HDR_GET_LEN(ip4_hdr);
} else {
size_t opts_len = full_ip6hdr_len - sizeof(struct ip6_header);
l4len = be16_to_cpu(ip6_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen) - opts_len;
}
return l4len > TCP_HEADER_DATA_OFFSET(tcp);
}
void eth_get_protocols(const struct iovec *iov, int iovcnt,
bool *isip4, bool *isip6,
bool *isudp, bool *istcp,
size_t *l3hdr_off,
size_t *l4hdr_off,
size_t *l5hdr_off,
eth_ip6_hdr_info *ip6hdr_info,
eth_ip4_hdr_info *ip4hdr_info,
eth_l4_hdr_info *l4hdr_info)
{
int proto;
bool fragment = false;
size_t l2hdr_len = eth_get_l2_hdr_length_iov(iov, iovcnt);
size_t input_size = iov_size(iov, iovcnt);
size_t copied;
*isip4 = *isip6 = *isudp = *istcp = false;
proto = eth_get_l3_proto(iov, iovcnt, l2hdr_len);
*l3hdr_off = l2hdr_len;
if (proto == ETH_P_IP) {
struct ip_header *iphdr = &ip4hdr_info->ip4_hdr;
if (input_size < l2hdr_len) {
return;
}
copied = iov_to_buf(iov, iovcnt, l2hdr_len, iphdr, sizeof(*iphdr));
*isip4 = true;
if (copied < sizeof(*iphdr)) {
return;
}
if (IP_HEADER_VERSION(iphdr) == IP_HEADER_VERSION_4) {
if (iphdr->ip_p == IP_PROTO_TCP) {
*istcp = true;
} else if (iphdr->ip_p == IP_PROTO_UDP) {
*isudp = true;
}
}
ip4hdr_info->fragment = IP4_IS_FRAGMENT(iphdr);
*l4hdr_off = l2hdr_len + IP_HDR_GET_LEN(iphdr);
fragment = ip4hdr_info->fragment;
} else if (proto == ETH_P_IPV6) {
*isip6 = true;
if (eth_parse_ipv6_hdr(iov, iovcnt, l2hdr_len,
ip6hdr_info)) {
if (ip6hdr_info->l4proto == IP_PROTO_TCP) {
*istcp = true;
} else if (ip6hdr_info->l4proto == IP_PROTO_UDP) {
*isudp = true;
}
} else {
return;
}
*l4hdr_off = l2hdr_len + ip6hdr_info->full_hdr_len;
fragment = ip6hdr_info->fragment;
}
if (!fragment) {
if (*istcp) {
*istcp = _eth_copy_chunk(input_size,
iov, iovcnt,
*l4hdr_off, sizeof(l4hdr_info->hdr.tcp),
&l4hdr_info->hdr.tcp);
if (*istcp) {
*l5hdr_off = *l4hdr_off +
TCP_HEADER_DATA_OFFSET(&l4hdr_info->hdr.tcp);
l4hdr_info->has_tcp_data =
_eth_tcp_has_data(proto == ETH_P_IP,
&ip4hdr_info->ip4_hdr,
&ip6hdr_info->ip6_hdr,
*l4hdr_off - *l3hdr_off,
&l4hdr_info->hdr.tcp);
}
} else if (*isudp) {
*isudp = _eth_copy_chunk(input_size,
iov, iovcnt,
*l4hdr_off, sizeof(l4hdr_info->hdr.udp),
&l4hdr_info->hdr.udp);
*l5hdr_off = *l4hdr_off + sizeof(l4hdr_info->hdr.udp);
}
}
}
size_t
eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t iovoff,
uint8_t *new_ehdr_buf,
uint16_t *payload_offset, uint16_t *tci)
{
struct vlan_header vlan_hdr;
struct eth_header *new_ehdr = (struct eth_header *) new_ehdr_buf;
size_t copied = iov_to_buf(iov, iovcnt, iovoff,
new_ehdr, sizeof(*new_ehdr));
if (copied < sizeof(*new_ehdr)) {
return 0;
}
switch (be16_to_cpu(new_ehdr->h_proto)) {
case ETH_P_VLAN:
case ETH_P_DVLAN:
copied = iov_to_buf(iov, iovcnt, iovoff + sizeof(*new_ehdr),
&vlan_hdr, sizeof(vlan_hdr));
if (copied < sizeof(vlan_hdr)) {
return 0;
}
new_ehdr->h_proto = vlan_hdr.h_proto;
*tci = be16_to_cpu(vlan_hdr.h_tci);
*payload_offset = iovoff + sizeof(*new_ehdr) + sizeof(vlan_hdr);
if (be16_to_cpu(new_ehdr->h_proto) == ETH_P_VLAN) {
copied = iov_to_buf(iov, iovcnt, *payload_offset,
PKT_GET_VLAN_HDR(new_ehdr), sizeof(vlan_hdr));
if (copied < sizeof(vlan_hdr)) {
return 0;
}
*payload_offset += sizeof(vlan_hdr);
return sizeof(struct eth_header) + sizeof(struct vlan_header);
} else {
return sizeof(struct eth_header);
}
default:
return 0;
}
}
size_t
eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff,
uint16_t vet, uint8_t *new_ehdr_buf,
uint16_t *payload_offset, uint16_t *tci)
{
struct vlan_header vlan_hdr;
struct eth_header *new_ehdr = (struct eth_header *) new_ehdr_buf;
size_t copied = iov_to_buf(iov, iovcnt, iovoff,
new_ehdr, sizeof(*new_ehdr));
if (copied < sizeof(*new_ehdr)) {
return 0;
}
if (be16_to_cpu(new_ehdr->h_proto) == vet) {
copied = iov_to_buf(iov, iovcnt, iovoff + sizeof(*new_ehdr),
&vlan_hdr, sizeof(vlan_hdr));
if (copied < sizeof(vlan_hdr)) {
return 0;
}
new_ehdr->h_proto = vlan_hdr.h_proto;
*tci = be16_to_cpu(vlan_hdr.h_tci);
*payload_offset = iovoff + sizeof(*new_ehdr) + sizeof(vlan_hdr);
return sizeof(struct eth_header);
}
return 0;
}
void
eth_setup_ip4_fragmentation(const void *l2hdr, size_t l2hdr_len,
void *l3hdr, size_t l3hdr_len,
size_t l3payload_len,
size_t frag_offset, bool more_frags)
{
const struct iovec l2vec = {
.iov_base = (void *) l2hdr,
.iov_len = l2hdr_len
};
if (eth_get_l3_proto(&l2vec, 1, l2hdr_len) == ETH_P_IP) {
uint16_t orig_flags;
struct ip_header *iphdr = (struct ip_header *) l3hdr;
uint16_t frag_off_units = frag_offset / IP_FRAG_UNIT_SIZE;
uint16_t new_ip_off;
assert(frag_offset % IP_FRAG_UNIT_SIZE == 0);
assert((frag_off_units & ~IP_OFFMASK) == 0);
orig_flags = be16_to_cpu(iphdr->ip_off) & ~(IP_OFFMASK|IP_MF);
new_ip_off = frag_off_units | orig_flags | (more_frags ? IP_MF : 0);
iphdr->ip_off = cpu_to_be16(new_ip_off);
iphdr->ip_len = cpu_to_be16(l3payload_len + l3hdr_len);
}
}
void
eth_fix_ip4_checksum(void *l3hdr, size_t l3hdr_len)
{
struct ip_header *iphdr = (struct ip_header *) l3hdr;
iphdr->ip_sum = 0;
iphdr->ip_sum = cpu_to_be16(net_raw_checksum(l3hdr, l3hdr_len));
}
uint32_t
eth_calc_ip4_pseudo_hdr_csum(struct ip_header *iphdr,
uint16_t csl,
uint32_t *cso)
{
struct ip_pseudo_header ipph;
ipph.ip_src = iphdr->ip_src;
ipph.ip_dst = iphdr->ip_dst;
ipph.ip_payload = cpu_to_be16(csl);
ipph.ip_proto = iphdr->ip_p;
ipph.zeros = 0;
*cso = sizeof(ipph);
return net_checksum_add(*cso, (uint8_t *) &ipph);
}
uint32_t
eth_calc_ip6_pseudo_hdr_csum(struct ip6_header *iphdr,
uint16_t csl,
uint8_t l4_proto,
uint32_t *cso)
{
struct ip6_pseudo_header ipph;
ipph.ip6_src = iphdr->ip6_src;
ipph.ip6_dst = iphdr->ip6_dst;
ipph.len = cpu_to_be16(csl);
ipph.zero[0] = 0;
ipph.zero[1] = 0;
ipph.zero[2] = 0;
ipph.next_hdr = l4_proto;
*cso = sizeof(ipph);
return net_checksum_add(*cso, (uint8_t *)&ipph);
}
static bool
eth_is_ip6_extension_header_type(uint8_t hdr_type)
{
switch (hdr_type) {
case IP6_HOP_BY_HOP:
case IP6_ROUTING:
case IP6_FRAGMENT:
case IP6_AUTHENTICATION:
case IP6_DESTINATON:
case IP6_MOBILITY:
return true;
default:
return false;
}
}
static bool
_eth_get_rss_ex_dst_addr(const struct iovec *pkt, int pkt_frags,
size_t ext_hdr_offset,
struct ip6_ext_hdr *ext_hdr,
struct in6_address *dst_addr)
{
struct ip6_ext_hdr_routing rt_hdr;
size_t input_size = iov_size(pkt, pkt_frags);
size_t bytes_read;
if (input_size < ext_hdr_offset + sizeof(rt_hdr) + sizeof(*dst_addr)) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags, ext_hdr_offset,
&rt_hdr, sizeof(rt_hdr));
assert(bytes_read == sizeof(rt_hdr));
if ((rt_hdr.rtype != 2) || (rt_hdr.segleft != 1)) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags, ext_hdr_offset + sizeof(rt_hdr),
dst_addr, sizeof(*dst_addr));
assert(bytes_read == sizeof(*dst_addr));
return true;
}
static bool
_eth_get_rss_ex_src_addr(const struct iovec *pkt, int pkt_frags,
size_t dsthdr_offset,
struct ip6_ext_hdr *ext_hdr,
struct in6_address *src_addr)
{
size_t bytes_left = (ext_hdr->ip6r_len + 1) * 8 - sizeof(*ext_hdr);
struct ip6_option_hdr opthdr;
size_t opt_offset = dsthdr_offset + sizeof(*ext_hdr);
while (bytes_left > sizeof(opthdr)) {
size_t input_size = iov_size(pkt, pkt_frags);
size_t bytes_read, optlen;
if (input_size < opt_offset) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags, opt_offset,
&opthdr, sizeof(opthdr));
if (bytes_read != sizeof(opthdr)) {
return false;
}
optlen = (opthdr.type == IP6_OPT_PAD1) ? 1
: (opthdr.len + sizeof(opthdr));
if (optlen > bytes_left) {
return false;
}
if (opthdr.type == IP6_OPT_HOME) {
size_t input_size = iov_size(pkt, pkt_frags);
if (input_size < opt_offset + sizeof(opthdr)) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags,
opt_offset + sizeof(opthdr),
src_addr, sizeof(*src_addr));
return bytes_read == sizeof(*src_addr);
}
opt_offset += optlen;
bytes_left -= optlen;
}
return false;
}
bool eth_parse_ipv6_hdr(const struct iovec *pkt, int pkt_frags,
size_t ip6hdr_off, eth_ip6_hdr_info *info)
{
struct ip6_ext_hdr ext_hdr;
size_t bytes_read;
uint8_t curr_ext_hdr_type;
size_t input_size = iov_size(pkt, pkt_frags);
info->rss_ex_dst_valid = false;
info->rss_ex_src_valid = false;
info->fragment = false;
if (input_size < ip6hdr_off) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off,
&info->ip6_hdr, sizeof(info->ip6_hdr));
if (bytes_read < sizeof(info->ip6_hdr)) {
return false;
}
info->full_hdr_len = sizeof(struct ip6_header);
curr_ext_hdr_type = info->ip6_hdr.ip6_nxt;
if (!eth_is_ip6_extension_header_type(curr_ext_hdr_type)) {
info->l4proto = info->ip6_hdr.ip6_nxt;
info->has_ext_hdrs = false;
return true;
}
info->has_ext_hdrs = true;
do {
if (input_size < ip6hdr_off + info->full_hdr_len) {
return false;
}
bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off + info->full_hdr_len,
&ext_hdr, sizeof(ext_hdr));
if (bytes_read < sizeof(ext_hdr)) {
return false;
}
if (curr_ext_hdr_type == IP6_ROUTING) {
if (ext_hdr.ip6r_len == sizeof(struct in6_address) / 8) {
info->rss_ex_dst_valid =
_eth_get_rss_ex_dst_addr(pkt, pkt_frags,
ip6hdr_off + info->full_hdr_len,
&ext_hdr, &info->rss_ex_dst);
}
} else if (curr_ext_hdr_type == IP6_DESTINATON) {
info->rss_ex_src_valid =
_eth_get_rss_ex_src_addr(pkt, pkt_frags,
ip6hdr_off + info->full_hdr_len,
&ext_hdr, &info->rss_ex_src);
} else if (curr_ext_hdr_type == IP6_FRAGMENT) {
info->fragment = true;
}
info->full_hdr_len += (ext_hdr.ip6r_len + 1) * IP6_EXT_GRANULARITY;
curr_ext_hdr_type = ext_hdr.ip6r_nxt;
} while (eth_is_ip6_extension_header_type(curr_ext_hdr_type));
info->l4proto = ext_hdr.ip6r_nxt;
return true;
}
bool eth_pad_short_frame(uint8_t *padded_pkt, size_t *padded_buflen,
const void *pkt, size_t pkt_size)
{
assert(padded_buflen && *padded_buflen >= ETH_ZLEN);
if (pkt_size >= ETH_ZLEN) {
return false;
}
/* pad to minimum Ethernet frame length */
memcpy(padded_pkt, pkt, pkt_size);
memset(&padded_pkt[pkt_size], 0, ETH_ZLEN - pkt_size);
*padded_buflen = ETH_ZLEN;
return true;
}
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