linux/net/ipv4/udp_offload.c
Jakub Sitnicki d51c5907e9 net, gro: Set inner transport header offset in tcp/udp GRO hook
GSO expects inner transport header offset to be valid when
skb->encapsulation flag is set. GSO uses this value to calculate the length
of an individual segment of a GSO packet in skb_gso_transport_seglen().

However, tcp/udp gro_complete callbacks don't update the
skb->inner_transport_header when processing an encapsulated TCP/UDP
segment. As a result a GRO skb has ->inner_transport_header set to a value
carried over from earlier skb processing.

This can have mild to tragic consequences. From miscalculating the GSO
segment length to triggering a page fault [1], when trying to read TCP/UDP
header at an address past the skb->data page.

The latter scenario leads to an oops report like so:

  BUG: unable to handle page fault for address: ffff9fa7ec00d008
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 123f201067 P4D 123f201067 PUD 123f209067 PMD 0
  Oops: 0000 [#1] SMP NOPTI
  CPU: 44 PID: 0 Comm: swapper/44 Not tainted 5.4.53-cloudflare-2020.7.21 #1
  Hardware name: HYVE EDGE-METAL-GEN10/HS-1811DLite1, BIOS V2.15 02/21/2020
  RIP: 0010:skb_gso_transport_seglen+0x44/0xa0
  Code: c0 41 83 e0 11 f6 87 81 00 00 00 20 74 30 0f b7 87 aa 00 00 00 0f [...]
  RSP: 0018:ffffad8640bacbb8 EFLAGS: 00010202
  RAX: 000000000000feda RBX: ffff9fcc8d31bc00 RCX: ffff9fa7ec00cffc
  RDX: ffff9fa7ebffdec0 RSI: 000000000000feda RDI: 0000000000000122
  RBP: 00000000000005c4 R08: 0000000000000001 R09: 0000000000000000
  R10: ffff9fe588ae3800 R11: ffff9fe011fc92f0 R12: ffff9fcc8d31bc00
  R13: ffff9fe0119d4300 R14: 00000000000005c4 R15: ffff9fba57d70900
  FS:  0000000000000000(0000) GS:ffff9fe68df00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffff9fa7ec00d008 CR3: 0000003e99b1c000 CR4: 0000000000340ee0
  Call Trace:
   <IRQ>
   skb_gso_validate_network_len+0x11/0x70
   __ip_finish_output+0x109/0x1c0
   ip_sublist_rcv_finish+0x57/0x70
   ip_sublist_rcv+0x2aa/0x2d0
   ? ip_rcv_finish_core.constprop.0+0x390/0x390
   ip_list_rcv+0x12b/0x14f
   __netif_receive_skb_list_core+0x2a9/0x2d0
   netif_receive_skb_list_internal+0x1b5/0x2e0
   napi_complete_done+0x93/0x140
   veth_poll+0xc0/0x19f [veth]
   ? mlx5e_napi_poll+0x221/0x610 [mlx5_core]
   net_rx_action+0x1f8/0x790
   __do_softirq+0xe1/0x2bf
   irq_exit+0x8e/0xc0
   do_IRQ+0x58/0xe0
   common_interrupt+0xf/0xf
   </IRQ>

The bug can be observed in a simple setup where we send IP/GRE/IP/TCP
packets into a netns over a veth pair. Inside the netns, packets are
forwarded to dummy device:

  trafgen -> [veth A]--[veth B] -forward-> [dummy]

For veth B to GRO aggregate packets on receive, it needs to have an XDP
program attached (for example, a trivial XDP_PASS). Additionally, for UDP,
we need to enable GSO_UDP_L4 feature on the device:

  ip netns exec A ethtool -K AB rx-udp-gro-forwarding on

The last component is an artificial delay to increase the chances of GRO
batching happening:

  ip netns exec A tc qdisc add dev AB root \
     netem delay 200us slot 5ms 10ms packets 2 bytes 64k

With such a setup in place, the bug can be observed by tracing the skb
outer and inner offsets when GSO skb is transmitted from the dummy device:

tcp:

FUNC              DEV   SKB_LEN  NH  TH ENC INH ITH GSO_SIZE GSO_TYPE
ip_finish_output  dumB     2830 270 290   1 294 254     1383 (tcpv4,gre,)
                                                ^^^
udp:

FUNC              DEV   SKB_LEN  NH  TH ENC INH ITH GSO_SIZE GSO_TYPE
ip_finish_output  dumB     2818 270 290   1 294 254     1383 (gre,udp_l4,)
                                                ^^^

Fix it by updating the inner transport header offset in tcp/udp
gro_complete callbacks, similar to how {inet,ipv6}_gro_complete callbacks
update the inner network header offset, when skb->encapsulation flag is
set.

[1] https://lore.kernel.org/netdev/CAKxSbF01cLpZem2GFaUaifh0S-5WYViZemTicAg7FCHOnh6kug@mail.gmail.com/

Fixes: bf296b125b ("tcp: Add GRO support")
Fixes: f993bc25e5 ("net: core: handle encapsulation offloads when computing segment lengths")
Fixes: e20cf8d3f1 ("udp: implement GRO for plain UDP sockets.")
Reported-by: Alex Forster <aforster@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-02 10:20:56 +01:00

716 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IPV4 GSO/GRO offload support
* Linux INET implementation
*
* UDPv4 GSO support
*/
#include <linux/skbuff.h>
#include <net/udp.h>
#include <net/protocol.h>
#include <net/inet_common.h>
static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
netdev_features_t features,
struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
netdev_features_t features),
__be16 new_protocol, bool is_ipv6)
{
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
bool remcsum, need_csum, offload_csum, gso_partial;
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct udphdr *uh = udp_hdr(skb);
u16 mac_offset = skb->mac_header;
__be16 protocol = skb->protocol;
u16 mac_len = skb->mac_len;
int udp_offset, outer_hlen;
__wsum partial;
bool need_ipsec;
if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
goto out;
/* Adjust partial header checksum to negate old length.
* We cannot rely on the value contained in uh->len as it is
* possible that the actual value exceeds the boundaries of the
* 16 bit length field due to the header being added outside of an
* IP or IPv6 frame that was already limited to 64K - 1.
*/
if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
partial = (__force __wsum)uh->len;
else
partial = (__force __wsum)htonl(skb->len);
partial = csum_sub(csum_unfold(uh->check), partial);
/* setup inner skb. */
skb->encapsulation = 0;
SKB_GSO_CB(skb)->encap_level = 0;
__skb_pull(skb, tnl_hlen);
skb_reset_mac_header(skb);
skb_set_network_header(skb, skb_inner_network_offset(skb));
skb_set_transport_header(skb, skb_inner_transport_offset(skb));
skb->mac_len = skb_inner_network_offset(skb);
skb->protocol = new_protocol;
need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
skb->encap_hdr_csum = need_csum;
remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
skb->remcsum_offload = remcsum;
need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
/* Try to offload checksum if possible */
offload_csum = !!(need_csum &&
!need_ipsec &&
(skb->dev->features &
(is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
(NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
features &= skb->dev->hw_enc_features;
if (need_csum)
features &= ~NETIF_F_SCTP_CRC;
/* The only checksum offload we care about from here on out is the
* outer one so strip the existing checksum feature flags and
* instead set the flag based on our outer checksum offload value.
*/
if (remcsum) {
features &= ~NETIF_F_CSUM_MASK;
if (!need_csum || offload_csum)
features |= NETIF_F_HW_CSUM;
}
/* segment inner packet. */
segs = gso_inner_segment(skb, features);
if (IS_ERR_OR_NULL(segs)) {
skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
mac_len);
goto out;
}
gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
outer_hlen = skb_tnl_header_len(skb);
udp_offset = outer_hlen - tnl_hlen;
skb = segs;
do {
unsigned int len;
if (remcsum)
skb->ip_summed = CHECKSUM_NONE;
/* Set up inner headers if we are offloading inner checksum */
if (skb->ip_summed == CHECKSUM_PARTIAL) {
skb_reset_inner_headers(skb);
skb->encapsulation = 1;
}
skb->mac_len = mac_len;
skb->protocol = protocol;
__skb_push(skb, outer_hlen);
skb_reset_mac_header(skb);
skb_set_network_header(skb, mac_len);
skb_set_transport_header(skb, udp_offset);
len = skb->len - udp_offset;
uh = udp_hdr(skb);
/* If we are only performing partial GSO the inner header
* will be using a length value equal to only one MSS sized
* segment instead of the entire frame.
*/
if (gso_partial && skb_is_gso(skb)) {
uh->len = htons(skb_shinfo(skb)->gso_size +
SKB_GSO_CB(skb)->data_offset +
skb->head - (unsigned char *)uh);
} else {
uh->len = htons(len);
}
if (!need_csum)
continue;
uh->check = ~csum_fold(csum_add(partial,
(__force __wsum)htonl(len)));
if (skb->encapsulation || !offload_csum) {
uh->check = gso_make_checksum(skb, ~uh->check);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
} else {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
}
} while ((skb = skb->next));
out:
return segs;
}
struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
netdev_features_t features,
bool is_ipv6)
{
__be16 protocol = skb->protocol;
const struct net_offload **offloads;
const struct net_offload *ops;
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
netdev_features_t features);
rcu_read_lock();
switch (skb->inner_protocol_type) {
case ENCAP_TYPE_ETHER:
protocol = skb->inner_protocol;
gso_inner_segment = skb_mac_gso_segment;
break;
case ENCAP_TYPE_IPPROTO:
offloads = is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[skb->inner_ipproto]);
if (!ops || !ops->callbacks.gso_segment)
goto out_unlock;
gso_inner_segment = ops->callbacks.gso_segment;
break;
default:
goto out_unlock;
}
segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
protocol, is_ipv6);
out_unlock:
rcu_read_unlock();
return segs;
}
EXPORT_SYMBOL(skb_udp_tunnel_segment);
static void __udpv4_gso_segment_csum(struct sk_buff *seg,
__be32 *oldip, __be32 *newip,
__be16 *oldport, __be16 *newport)
{
struct udphdr *uh;
struct iphdr *iph;
if (*oldip == *newip && *oldport == *newport)
return;
uh = udp_hdr(seg);
iph = ip_hdr(seg);
if (uh->check) {
inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
true);
inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
false);
if (!uh->check)
uh->check = CSUM_MANGLED_0;
}
*oldport = *newport;
csum_replace4(&iph->check, *oldip, *newip);
*oldip = *newip;
}
static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
{
struct sk_buff *seg;
struct udphdr *uh, *uh2;
struct iphdr *iph, *iph2;
seg = segs;
uh = udp_hdr(seg);
iph = ip_hdr(seg);
if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
(udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
(ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
(ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
return segs;
while ((seg = seg->next)) {
uh2 = udp_hdr(seg);
iph2 = ip_hdr(seg);
__udpv4_gso_segment_csum(seg,
&iph2->saddr, &iph->saddr,
&uh2->source, &uh->source);
__udpv4_gso_segment_csum(seg,
&iph2->daddr, &iph->daddr,
&uh2->dest, &uh->dest);
}
return segs;
}
static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
netdev_features_t features,
bool is_ipv6)
{
unsigned int mss = skb_shinfo(skb)->gso_size;
skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
if (IS_ERR(skb))
return skb;
udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
}
struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
netdev_features_t features, bool is_ipv6)
{
struct sock *sk = gso_skb->sk;
unsigned int sum_truesize = 0;
struct sk_buff *segs, *seg;
struct udphdr *uh;
unsigned int mss;
bool copy_dtor;
__sum16 check;
__be16 newlen;
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)
return ERR_PTR(-EINVAL);
skb_pull(gso_skb, sizeof(*uh));
/* clear destructor to avoid skb_segment assigning it to tail */
copy_dtor = gso_skb->destructor == sock_wfree;
if (copy_dtor)
gso_skb->destructor = NULL;
segs = skb_segment(gso_skb, features);
if (IS_ERR_OR_NULL(segs)) {
if (copy_dtor)
gso_skb->destructor = sock_wfree;
return segs;
}
/* GSO partial and frag_list segmentation only requires splitting
* the frame into an MSS multiple and possibly a remainder, both
* cases return a GSO skb. So update the mss now.
*/
if (skb_is_gso(segs))
mss *= skb_shinfo(segs)->gso_segs;
seg = segs;
uh = udp_hdr(seg);
/* preserve TX timestamp flags and TS key for first segment */
skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
skb_shinfo(seg)->tx_flags |=
(skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
/* compute checksum adjustment based on old length versus new */
newlen = htons(sizeof(*uh) + mss);
check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
for (;;) {
if (copy_dtor) {
seg->destructor = sock_wfree;
seg->sk = sk;
sum_truesize += seg->truesize;
}
if (!seg->next)
break;
uh->len = newlen;
uh->check = check;
if (seg->ip_summed == CHECKSUM_PARTIAL)
gso_reset_checksum(seg, ~check);
else
uh->check = gso_make_checksum(seg, ~check) ? :
CSUM_MANGLED_0;
seg = seg->next;
uh = udp_hdr(seg);
}
/* last packet can be partial gso_size, account for that in checksum */
newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
seg->data_len);
check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
uh->len = newlen;
uh->check = check;
if (seg->ip_summed == CHECKSUM_PARTIAL)
gso_reset_checksum(seg, ~check);
else
uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
/* update refcount for the packet */
if (copy_dtor) {
int delta = sum_truesize - gso_skb->truesize;
/* In some pathological cases, delta can be negative.
* We need to either use refcount_add() or refcount_sub_and_test()
*/
if (likely(delta >= 0))
refcount_add(delta, &sk->sk_wmem_alloc);
else
WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
}
return segs;
}
EXPORT_SYMBOL_GPL(__udp_gso_segment);
static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int mss;
__wsum csum;
struct udphdr *uh;
struct iphdr *iph;
if (skb->encapsulation &&
(skb_shinfo(skb)->gso_type &
(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
segs = skb_udp_tunnel_segment(skb, features, false);
goto out;
}
if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
goto out;
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
return __udp_gso_segment(skb, features, false);
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
goto out;
/* Do software UFO. Complete and fill in the UDP checksum as
* HW cannot do checksum of UDP packets sent as multiple
* IP fragments.
*/
uh = udp_hdr(skb);
iph = ip_hdr(skb);
uh->check = 0;
csum = skb_checksum(skb, 0, skb->len, 0);
uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_UNNECESSARY;
/* If there is no outer header we can fake a checksum offload
* due to the fact that we have already done the checksum in
* software prior to segmenting the frame.
*/
if (!skb->encap_hdr_csum)
features |= NETIF_F_HW_CSUM;
/* Fragment the skb. IP headers of the fragments are updated in
* inet_gso_segment()
*/
segs = skb_segment(skb, features);
out:
return segs;
}
#define UDP_GRO_CNT_MAX 64
static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
struct sk_buff *skb)
{
struct udphdr *uh = udp_gro_udphdr(skb);
struct sk_buff *pp = NULL;
struct udphdr *uh2;
struct sk_buff *p;
unsigned int ulen;
int ret = 0;
/* requires non zero csum, for symmetry with GSO */
if (!uh->check) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
/* Do not deal with padded or malicious packets, sorry ! */
ulen = ntohs(uh->len);
if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
/* pull encapsulating udp header */
skb_gro_pull(skb, sizeof(struct udphdr));
list_for_each_entry(p, head, list) {
if (!NAPI_GRO_CB(p)->same_flow)
continue;
uh2 = udp_hdr(p);
/* Match ports only, as csum is always non zero */
if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
NAPI_GRO_CB(skb)->flush = 1;
return p;
}
/* Terminate the flow on len mismatch or if it grow "too much".
* Under small packet flood GRO count could elsewhere grow a lot
* leading to excessive truesize values.
* On len mismatch merge the first packet shorter than gso_size,
* otherwise complete the GRO packet.
*/
if (ulen > ntohs(uh2->len)) {
pp = p;
} else {
if (NAPI_GRO_CB(skb)->is_flist) {
if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
if ((skb->ip_summed != p->ip_summed) ||
(skb->csum_level != p->csum_level)) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
ret = skb_gro_receive_list(p, skb);
} else {
skb_gro_postpull_rcsum(skb, uh,
sizeof(struct udphdr));
ret = skb_gro_receive(p, skb);
}
}
if (ret || ulen != ntohs(uh2->len) ||
NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
pp = p;
return pp;
}
/* mismatch, but we never need to flush */
return NULL;
}
struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, struct sock *sk)
{
struct sk_buff *pp = NULL;
struct sk_buff *p;
struct udphdr *uh2;
unsigned int off = skb_gro_offset(skb);
int flush = 1;
/* we can do L4 aggregation only if the packet can't land in a tunnel
* otherwise we could corrupt the inner stream
*/
NAPI_GRO_CB(skb)->is_flist = 0;
if (!sk || !udp_sk(sk)->gro_receive) {
if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled : 1;
if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
(sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
return call_gro_receive(udp_gro_receive_segment, head, skb);
/* no GRO, be sure flush the current packet */
goto out;
}
if (NAPI_GRO_CB(skb)->encap_mark ||
(uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
NAPI_GRO_CB(skb)->csum_cnt == 0 &&
!NAPI_GRO_CB(skb)->csum_valid))
goto out;
/* mark that this skb passed once through the tunnel gro layer */
NAPI_GRO_CB(skb)->encap_mark = 1;
flush = 0;
list_for_each_entry(p, head, list) {
if (!NAPI_GRO_CB(p)->same_flow)
continue;
uh2 = (struct udphdr *)(p->data + off);
/* Match ports and either checksums are either both zero
* or nonzero.
*/
if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
(!uh->check ^ !uh2->check)) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
}
skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
out:
skb_gro_flush_final(skb, pp, flush);
return pp;
}
EXPORT_SYMBOL(udp_gro_receive);
static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
__be16 dport)
{
const struct iphdr *iph = skb_gro_network_header(skb);
return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
iph->daddr, dport, inet_iif(skb),
inet_sdif(skb), &udp_table, NULL);
}
INDIRECT_CALLABLE_SCOPE
struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
{
struct udphdr *uh = udp_gro_udphdr(skb);
struct sock *sk = NULL;
struct sk_buff *pp;
if (unlikely(!uh))
goto flush;
/* Don't bother verifying checksum if we're going to flush anyway. */
if (NAPI_GRO_CB(skb)->flush)
goto skip;
if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
inet_gro_compute_pseudo))
goto flush;
else if (uh->check)
skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
inet_gro_compute_pseudo);
skip:
NAPI_GRO_CB(skb)->is_ipv6 = 0;
rcu_read_lock();
if (static_branch_unlikely(&udp_encap_needed_key))
sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
pp = udp_gro_receive(head, skb, uh, sk);
rcu_read_unlock();
return pp;
flush:
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
static int udp_gro_complete_segment(struct sk_buff *skb)
{
struct udphdr *uh = udp_hdr(skb);
skb->csum_start = (unsigned char *)uh - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
if (skb->encapsulation)
skb->inner_transport_header = skb->transport_header;
return 0;
}
int udp_gro_complete(struct sk_buff *skb, int nhoff,
udp_lookup_t lookup)
{
__be16 newlen = htons(skb->len - nhoff);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
struct sock *sk;
int err;
uh->len = newlen;
rcu_read_lock();
sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
udp4_lib_lookup_skb, skb, uh->source, uh->dest);
if (sk && udp_sk(sk)->gro_complete) {
skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
: SKB_GSO_UDP_TUNNEL;
/* clear the encap mark, so that inner frag_list gro_complete
* can take place
*/
NAPI_GRO_CB(skb)->encap_mark = 0;
/* Set encapsulation before calling into inner gro_complete()
* functions to make them set up the inner offsets.
*/
skb->encapsulation = 1;
err = udp_sk(sk)->gro_complete(sk, skb,
nhoff + sizeof(struct udphdr));
} else {
err = udp_gro_complete_segment(skb);
}
rcu_read_unlock();
if (skb->remcsum_offload)
skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
return err;
}
EXPORT_SYMBOL(udp_gro_complete);
INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct iphdr *iph = ip_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
/* do fraglist only if there is no outer UDP encap (or we already processed it) */
if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
uh->len = htons(skb->len - nhoff);
skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
skb->csum_level++;
} else {
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->csum_level = 0;
}
return 0;
}
if (uh->check)
uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
iph->daddr, 0);
return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
}
static const struct net_offload udpv4_offload = {
.callbacks = {
.gso_segment = udp4_ufo_fragment,
.gro_receive = udp4_gro_receive,
.gro_complete = udp4_gro_complete,
},
};
int __init udpv4_offload_init(void)
{
return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
}