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ipv6: Add generic UDP Tunnel segmentation
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Similar to commit 7313626
(tunneling: Add generic Tunnel segmentation)

This patch adds generic tunneling offloading support for
IPv6-UDP based tunnels.

This can be used by tunneling protocols like VXLAN.

Cc: Jesse Gross <jesse@nicira.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Cong Wang authored and David S. Miller committed Sep 1, 2013
1 parent f564f45 commit d949d82
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Showing 2 changed files with 111 additions and 52 deletions.
4 changes: 3 additions & 1 deletion net/ipv6/ip6_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
unsigned int unfrag_ip6hlen;
u8 *prevhdr;
int offset = 0;
bool tunnel;

if (unlikely(skb_shinfo(skb)->gso_type &
~(SKB_GSO_UDP |
Expand All @@ -106,6 +107,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
goto out;

tunnel = skb->encapsulation;
ipv6h = ipv6_hdr(skb);
__skb_pull(skb, sizeof(*ipv6h));
segs = ERR_PTR(-EPROTONOSUPPORT);
Expand All @@ -126,7 +128,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
ipv6h = ipv6_hdr(skb);
ipv6h->payload_len = htons(skb->len - skb->mac_len -
sizeof(*ipv6h));
if (proto == IPPROTO_UDP) {
if (!tunnel && proto == IPPROTO_UDP) {
unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
fptr = (struct frag_hdr *)(skb_network_header(skb) +
unfrag_ip6hlen);
Expand Down
159 changes: 108 additions & 51 deletions net/ipv6/udp_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,26 +21,79 @@ static int udp6_ufo_send_check(struct sk_buff *skb)
const struct ipv6hdr *ipv6h;
struct udphdr *uh;

/* UDP Tunnel offload on ipv6 is not yet supported. */
if (skb->encapsulation)
return -EINVAL;

if (!pskb_may_pull(skb, sizeof(*uh)))
return -EINVAL;

ipv6h = ipv6_hdr(skb);
uh = udp_hdr(skb);
if (likely(!skb->encapsulation)) {
ipv6h = ipv6_hdr(skb);
uh = udp_hdr(skb);

uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
IPPROTO_UDP, 0);
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
}

uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
IPPROTO_UDP, 0);
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
return 0;
}

static struct sk_buff *skb_udp6_tunnel_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
int mac_len = skb->mac_len;
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
int outer_hlen;
netdev_features_t enc_features;

if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
goto out;

skb->encapsulation = 0;
__skb_pull(skb, tnl_hlen);
skb_reset_mac_header(skb);
skb_set_network_header(skb, skb_inner_network_offset(skb));
skb->mac_len = skb_inner_network_offset(skb);

/* segment inner packet. */
enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
segs = skb_mac_gso_segment(skb, enc_features);
if (!segs || IS_ERR(segs))
goto out;

outer_hlen = skb_tnl_header_len(skb);
skb = segs;
do {
struct udphdr *uh;
struct ipv6hdr *ipv6h;
int udp_offset = outer_hlen - tnl_hlen;
u32 len;

skb->mac_len = mac_len;

skb_push(skb, outer_hlen);
skb_reset_mac_header(skb);
skb_set_network_header(skb, mac_len);
skb_set_transport_header(skb, udp_offset);
uh = udp_hdr(skb);
uh->len = htons(skb->len - udp_offset);
ipv6h = ipv6_hdr(skb);
len = skb->len - udp_offset;

uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
len, IPPROTO_UDP, 0);
uh->check = csum_fold(skb_checksum(skb, udp_offset, len, 0));
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_NONE;
} while ((skb = skb->next));
out:
return segs;
}

static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
netdev_features_t features)
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int mss;
Expand Down Expand Up @@ -75,47 +128,51 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
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.
*/
offset = skb_checksum_start_offset(skb);
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
skb->ip_summed = CHECKSUM_NONE;

/* Check if there is enough headroom to insert fragment header. */
tnl_hlen = skb_tnl_header_len(skb);
if (skb_headroom(skb) < (tnl_hlen + frag_hdr_sz)) {
if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
goto out;
if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
segs = skb_udp6_tunnel_segment(skb, features);
else {
/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
* do checksum of UDP packets sent as multiple IP fragments.
*/
offset = skb_checksum_start_offset(skb);
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
skb->ip_summed = CHECKSUM_NONE;

/* Check if there is enough headroom to insert fragment header. */
tnl_hlen = skb_tnl_header_len(skb);
if (skb_headroom(skb) < (tnl_hlen + frag_hdr_sz)) {
if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
goto out;
}

/* Find the unfragmentable header and shift it left by frag_hdr_sz
* bytes to insert fragment header.
*/
unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
nexthdr = *prevhdr;
*prevhdr = NEXTHDR_FRAGMENT;
unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
unfrag_ip6hlen + tnl_hlen;
packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);

SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
skb->mac_header -= frag_hdr_sz;
skb->network_header -= frag_hdr_sz;

fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
fptr->nexthdr = nexthdr;
fptr->reserved = 0;
ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));

/* Fragment the skb. ipv6 header and the remaining fields of the
* fragment header are updated in ipv6_gso_segment()
*/
segs = skb_segment(skb, features);
}

/* Find the unfragmentable header and shift it left by frag_hdr_sz
* bytes to insert fragment header.
*/
unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
nexthdr = *prevhdr;
*prevhdr = NEXTHDR_FRAGMENT;
unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
unfrag_ip6hlen + tnl_hlen;
packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);

SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
skb->mac_header -= frag_hdr_sz;
skb->network_header -= frag_hdr_sz;

fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
fptr->nexthdr = nexthdr;
fptr->reserved = 0;
ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));

/* Fragment the skb. ipv6 header and the remaining fields of the
* fragment header are updated in ipv6_gso_segment()
*/
segs = skb_segment(skb, features);

out:
return segs;
}
Expand Down

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