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udp: Support UDP fraglist GRO/GSO.
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This patch extends UDP GRO to support fraglist GRO/GSO
by using the previously introduced infrastructure.
If the feature is enabled, all UDP packets are going to
fraglist GRO (local input and forward).

After validating the csum,  we mark ip_summed as
CHECKSUM_UNNECESSARY for fraglist GRO packets to
make sure that the csum is not touched.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@klassert @davem330
klassert authored and davem330 committed Jan 27, 2020
1 parent 3a1296a commit 9fd1ff5
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Showing 3 changed files with 107 additions and 26 deletions.
2 changes: 1 addition & 1 deletion include/net/udp.h
View file
Expand Up @@ -167,7 +167,7 @@ typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
__be16 dport);

struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, udp_lookup_t lookup);
struct udphdr *uh, struct sock *sk);
int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);

struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
Expand Down
104 changes: 81 additions & 23 deletions net/ipv4/udp_offload.c
View file
Expand Up @@ -184,6 +184,20 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
}
EXPORT_SYMBOL(skb_udp_tunnel_segment);

static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
netdev_features_t features)
{
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 skb;
}

struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
netdev_features_t features)
{
Expand All @@ -196,6 +210,9 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
__sum16 check;
__be16 newlen;

if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
return __udp_gso_segment_list(gso_skb, features);

mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)
return ERR_PTR(-EINVAL);
Expand Down Expand Up @@ -354,6 +371,7 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
struct udphdr *uh2;
struct sk_buff *p;
unsigned int ulen;
int ret = 0;

/* requires non zero csum, for symmetry with GSO */
if (!uh->check) {
Expand All @@ -369,7 +387,6 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
}
/* pull encapsulating udp header */
skb_gro_pull(skb, sizeof(struct udphdr));
skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));

list_for_each_entry(p, head, list) {
if (!NAPI_GRO_CB(p)->same_flow)
Expand All @@ -383,14 +400,40 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
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) || skb_gro_receive(p, skb) ||
ulen != ntohs(uh2->len) ||
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;

Expand All @@ -401,36 +444,29 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
return NULL;
}

INDIRECT_CALLABLE_DECLARE(struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport));
struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, udp_lookup_t lookup)
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;
struct sock *sk;

rcu_read_lock();
sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
udp4_lib_lookup_skb, skb, uh->source, uh->dest);
if (!sk)
goto out_unlock;
if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;

if (udp_sk(sk)->gro_enabled) {
if ((sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist) {
pp = call_gro_receive(udp_gro_receive_segment, head, skb);
rcu_read_unlock();
return pp;
}

if (NAPI_GRO_CB(skb)->encap_mark ||
if (!sk || NAPI_GRO_CB(skb)->encap_mark ||
(skb->ip_summed != CHECKSUM_PARTIAL &&
NAPI_GRO_CB(skb)->csum_cnt == 0 &&
!NAPI_GRO_CB(skb)->csum_valid) ||
!udp_sk(sk)->gro_receive)
goto out_unlock;
goto out;

/* mark that this skb passed once through the tunnel gro layer */
NAPI_GRO_CB(skb)->encap_mark = 1;
Expand All @@ -457,8 +493,7 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);

out_unlock:
rcu_read_unlock();
out:
skb_gro_flush_final(skb, pp, flush);
return pp;
}
Expand All @@ -468,8 +503,10 @@ 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 sk_buff *pp;
struct sock *sk;

if (unlikely(!uh) || !static_branch_unlikely(&udp_encap_needed_key))
if (unlikely(!uh))
goto flush;

/* Don't bother verifying checksum if we're going to flush anyway. */
Expand All @@ -484,7 +521,11 @@ struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
inet_gro_compute_pseudo);
skip:
NAPI_GRO_CB(skb)->is_ipv6 = 0;
return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
rcu_read_lock();
sk = static_branch_unlikely(&udp_encap_needed_key) ? udp4_lib_lookup_skb(skb, uh->source, uh->dest) : NULL;
pp = udp_gro_receive(head, skb, uh, sk);
rcu_read_unlock();
return pp;

flush:
NAPI_GRO_CB(skb)->flush = 1;
Expand Down Expand Up @@ -517,9 +558,7 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
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_enabled) {
err = udp_gro_complete_segment(skb);
} else if (sk && udp_sk(sk)->gro_complete) {
if (sk && udp_sk(sk)->gro_complete) {
skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
: SKB_GSO_UDP_TUNNEL;

Expand All @@ -529,6 +568,8 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
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();

Expand All @@ -544,6 +585,23 @@ 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);

if (NAPI_GRO_CB(skb)->is_flist) {
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);
Expand Down
27 changes: 25 additions & 2 deletions net/ipv6/udp_offload.c
View file
Expand Up @@ -115,8 +115,10 @@ INDIRECT_CALLABLE_SCOPE
struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb)
{
struct udphdr *uh = udp_gro_udphdr(skb);
struct sk_buff *pp;
struct sock *sk;

if (unlikely(!uh) || !static_branch_unlikely(&udpv6_encap_needed_key))
if (unlikely(!uh))
goto flush;

/* Don't bother verifying checksum if we're going to flush anyway. */
Expand All @@ -132,7 +134,11 @@ struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb)

skip:
NAPI_GRO_CB(skb)->is_ipv6 = 1;
return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
rcu_read_lock();
sk = static_branch_unlikely(&udpv6_encap_needed_key) ? udp6_lib_lookup_skb(skb, uh->source, uh->dest) : NULL;
pp = udp_gro_receive(head, skb, uh, sk);
rcu_read_unlock();
return pp;

flush:
NAPI_GRO_CB(skb)->flush = 1;
Expand All @@ -144,6 +150,23 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);

if (NAPI_GRO_CB(skb)->is_flist) {
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_v6_check(skb->len - nhoff, &ipv6h->saddr,
&ipv6h->daddr, 0);
Expand Down

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