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;
int offset;
__wsum csum;
if (skb->encapsulation &&
skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
segs = skb_udp_tunnel_segment(skb, features);
goto out;
}
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
goto out;
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_GRE | SKB_GSO_MPLS) ||
!(type & (SKB_GSO_UDP))))
goto out;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
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;
/* Fragment the skb. IP headers of the fragments are updated in
* inet_gso_segment()
*/
segs = skb_segment(skb, features);
out:
return segs;
}
static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct sctphdr *sh;
sh = sctp_hdr(skb);
if (!pskb_may_pull(skb, sizeof(*sh)))
goto out;
__skb_pull(skb, sizeof(*sh));
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
struct skb_shared_info *pinfo = skb_shinfo(skb);
struct sk_buff *frag_iter;
pinfo->gso_segs = 0;
if (skb->len != skb->data_len) {
/* Means we have chunks in here too */
pinfo->gso_segs++;
}
skb_walk_frags(skb, frag_iter)
pinfo->gso_segs++;
segs = NULL;
goto out;
}
segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
if (IS_ERR(segs))
goto out;
/* All that is left is update SCTP CRC if necessary */
if (!(features & NETIF_F_SCTP_CRC)) {
for (skb = segs; skb; skb = skb->next) {
if (skb->ip_summed == CHECKSUM_PARTIAL) {
sh = sctp_hdr(skb);
sh->checksum = sctp_gso_make_checksum(skb);
}
}
}
out:
return segs;
}
struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int sum_truesize = 0;
struct tcphdr *th;
unsigned int thlen;
unsigned int seq;
__be32 delta;
unsigned int oldlen;
unsigned int mss;
struct sk_buff *gso_skb = skb;
__sum16 newcheck;
bool ooo_okay, copy_destructor;
if (!pskb_may_pull(skb, sizeof(*th)))
goto out;
th = tcp_hdr(skb);
thlen = th->doff * 4;
if (thlen < sizeof(*th))
goto out;
if (!pskb_may_pull(skb, thlen))
goto out;
oldlen = (u16)~skb->len;
__skb_pull(skb, thlen);
mss = tcp_skb_mss(skb);
if (unlikely(skb->len <= mss))
goto out;
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
if (unlikely(type &
~(SKB_GSO_TCPV4 |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCPV6 |
SKB_GSO_GRE |
SKB_GSO_IPIP |
SKB_GSO_SIT |
SKB_GSO_MPLS |
SKB_GSO_UDP_TUNNEL |
0) ||
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
goto out;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
goto out;
}
copy_destructor = gso_skb->destructor == tcp_wfree;
ooo_okay = gso_skb->ooo_okay;
/* All segments but the first should have ooo_okay cleared */
skb->ooo_okay = 0;
segs = skb_segment(skb, features);
if (IS_ERR(segs))
goto out;
/* Only first segment might have ooo_okay set */
segs->ooo_okay = ooo_okay;
delta = htonl(oldlen + (thlen + mss));
skb = segs;
th = tcp_hdr(skb);
seq = ntohl(th->seq);
newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
do {
th->fin = th->psh = 0;
th->check = newcheck;
if (skb->ip_summed != CHECKSUM_PARTIAL)
th->check =
csum_fold(csum_partial(skb_transport_header(skb),
thlen, skb->csum));
seq += mss;
if (copy_destructor) {
skb->destructor = gso_skb->destructor;
skb->sk = gso_skb->sk;
sum_truesize += skb->truesize;
}
skb = skb->next;
th = tcp_hdr(skb);
th->seq = htonl(seq);
th->cwr = 0;
} while (skb->next);
/* Following permits TCP Small Queues to work well with GSO :
* The callback to TCP stack will be called at the time last frag
* is freed at TX completion, and not right now when gso_skb
* is freed by GSO engine
*/
if (copy_destructor) {
swap(gso_skb->sk, skb->sk);
swap(gso_skb->destructor, skb->destructor);
sum_truesize += skb->truesize;
atomic_add(sum_truesize - gso_skb->truesize,
&skb->sk->sk_wmem_alloc);
}
delta = htonl(oldlen + (skb_tail_pointer(skb) -
skb_transport_header(skb)) +
skb->data_len);
th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
if (skb->ip_summed != CHECKSUM_PARTIAL)
th->check = csum_fold(csum_partial(skb_transport_header(skb),
thlen, skb->csum));
out:
return segs;
}
struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int sum_truesize = 0;
struct tcphdr *th;
unsigned int thlen;
unsigned int seq;
__be32 delta;
unsigned int oldlen;
unsigned int mss;
struct sk_buff *gso_skb = skb;
__sum16 newcheck;
bool ooo_okay, copy_destructor;
th = tcp_hdr(skb);
thlen = th->doff * 4;
if (thlen < sizeof(*th))
goto out;
if (!pskb_may_pull(skb, thlen))
goto out;
oldlen = (u16)~skb->len;
__skb_pull(skb, thlen);
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
goto out;
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
goto out;
}
copy_destructor = gso_skb->destructor == tcp_wfree;
ooo_okay = gso_skb->ooo_okay;
/* All segments but the first should have ooo_okay cleared */
skb->ooo_okay = 0;
segs = skb_segment(skb, features);
if (IS_ERR(segs))
goto out;
/* Only first segment might have ooo_okay set */
segs->ooo_okay = ooo_okay;
/* 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;
delta = htonl(oldlen + (thlen + mss));
skb = segs;
th = tcp_hdr(skb);
seq = ntohl(th->seq);
if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
while (skb->next) {
th->fin = th->psh = 0;
th->check = newcheck;
if (skb->ip_summed == CHECKSUM_PARTIAL)
gso_reset_checksum(skb, ~th->check);
else
th->check = gso_make_checksum(skb, ~th->check);
seq += mss;
if (copy_destructor) {
skb->destructor = gso_skb->destructor;
skb->sk = gso_skb->sk;
sum_truesize += skb->truesize;
}
skb = skb->next;
th = tcp_hdr(skb);
th->seq = htonl(seq);
th->cwr = 0;
}
/* Following permits TCP Small Queues to work well with GSO :
* The callback to TCP stack will be called at the time last frag
* is freed at TX completion, and not right now when gso_skb
* is freed by GSO engine
*/
if (copy_destructor) {
swap(gso_skb->sk, skb->sk);
swap(gso_skb->destructor, skb->destructor);
sum_truesize += skb->truesize;
atomic_add(sum_truesize - gso_skb->truesize,
&skb->sk->sk_wmem_alloc);
}
delta = htonl(oldlen + (skb_tail_pointer(skb) -
skb_transport_header(skb)) +
skb->data_len);
th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
if (skb->ip_summed == CHECKSUM_PARTIAL)
gso_reset_checksum(skb, ~th->check);
else
th->check = gso_make_checksum(skb, ~th->check);
out:
return segs;
}
static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int mss;
unsigned int unfrag_ip6hlen, unfrag_len;
struct frag_hdr *fptr;
u8 *packet_start, *prevhdr;
u8 nexthdr;
u8 frag_hdr_sz = sizeof(struct frag_hdr);
__wsum csum;
int tnl_hlen;
int err;
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
goto out;
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
/* Set the IPv6 fragment id if not set yet */
if (!skb_shinfo(skb)->ip6_frag_id)
ipv6_proxy_select_ident(dev_net(skb->dev), skb);
segs = NULL;
goto out;
}
if (skb->encapsulation && skb_shinfo(skb)->gso_type &
(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
segs = skb_udp_tunnel_segment(skb, features, true);
else {
const struct ipv6hdr *ipv6h;
struct udphdr *uh;
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
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);
ipv6h = ipv6_hdr(skb);
uh->check = 0;
csum = skb_checksum(skb, 0, skb->len, 0);
uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
&ipv6h->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;
/* Check if there is enough headroom to insert fragment header. */
tnl_hlen = skb_tnl_header_len(skb);
if (skb->mac_header < (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.
*/
err = ip6_find_1stfragopt(skb, &prevhdr);
if (err < 0)
return ERR_PTR(err);
unfrag_ip6hlen = err;
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;
if (!skb_shinfo(skb)->ip6_frag_id)
ipv6_proxy_select_ident(dev_net(skb->dev), skb);
fptr->identification = skb_shinfo(skb)->ip6_frag_id;
/* 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;
}
static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int mss;
unsigned int unfrag_ip6hlen, unfrag_len;
struct frag_hdr *fptr;
u8 *packet_start, *prevhdr;
u8 nexthdr;
u8 frag_hdr_sz = sizeof(struct frag_hdr);
__wsum csum;
int tnl_hlen;
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
goto out;
if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
if (unlikely(type & ~(SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_UDP_TUNNEL_CSUM |
SKB_GSO_GRE |
SKB_GSO_GRE_CSUM |
SKB_GSO_IPIP |
SKB_GSO_SIT |
SKB_GSO_MPLS) ||
!(type & (SKB_GSO_UDP))))
goto out;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
segs = NULL;
goto out;
}
if (skb->encapsulation && skb_shinfo(skb)->gso_type &
(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
segs = skb_udp_tunnel_segment(skb, features, true);
else {
const struct ipv6hdr *ipv6h;
struct udphdr *uh;
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
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);
ipv6h = ipv6_hdr(skb);
uh->check = 0;
csum = skb_checksum(skb, 0, skb->len, 0);
uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
&ipv6h->daddr, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_NONE;
/* Check if there is enough headroom to insert fragment header. */
tnl_hlen = skb_tnl_header_len(skb);
if (skb->mac_header < (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;
fptr->identification = skb_shinfo(skb)->ip6_frag_id;
/* 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;
}