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348 lines
8.2 KiB
348 lines
8.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* IPV4 GSO/GRO offload support |
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* Linux INET implementation |
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* |
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* TCPv4 GSO/GRO support |
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*/ |
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#include <linux/indirect_call_wrapper.h> |
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#include <linux/skbuff.h> |
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#include <net/tcp.h> |
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#include <net/protocol.h> |
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static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq, |
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unsigned int seq, unsigned int mss) |
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{ |
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while (skb) { |
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if (before(ts_seq, seq + mss)) { |
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skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP; |
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skb_shinfo(skb)->tskey = ts_seq; |
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return; |
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} |
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skb = skb->next; |
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seq += mss; |
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} |
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} |
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static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb, |
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netdev_features_t features) |
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{ |
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)) |
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return ERR_PTR(-EINVAL); |
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if (!pskb_may_pull(skb, sizeof(struct tcphdr))) |
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return ERR_PTR(-EINVAL); |
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if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) { |
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const struct iphdr *iph = ip_hdr(skb); |
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struct tcphdr *th = tcp_hdr(skb); |
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/* Set up checksum pseudo header, usually expect stack to |
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* have done this already. |
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*/ |
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th->check = 0; |
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skb->ip_summed = CHECKSUM_PARTIAL; |
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__tcp_v4_send_check(skb, iph->saddr, iph->daddr); |
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} |
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return tcp_gso_segment(skb, features); |
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} |
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struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
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netdev_features_t features) |
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{ |
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struct sk_buff *segs = ERR_PTR(-EINVAL); |
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unsigned int sum_truesize = 0; |
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struct tcphdr *th; |
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unsigned int thlen; |
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unsigned int seq; |
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__be32 delta; |
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unsigned int oldlen; |
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unsigned int mss; |
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struct sk_buff *gso_skb = skb; |
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__sum16 newcheck; |
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bool ooo_okay, copy_destructor; |
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th = tcp_hdr(skb); |
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thlen = th->doff * 4; |
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if (thlen < sizeof(*th)) |
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goto out; |
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if (!pskb_may_pull(skb, thlen)) |
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goto out; |
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oldlen = (u16)~skb->len; |
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__skb_pull(skb, thlen); |
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mss = skb_shinfo(skb)->gso_size; |
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if (unlikely(skb->len <= mss)) |
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goto out; |
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { |
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/* Packet is from an untrusted source, reset gso_segs. */ |
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skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); |
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segs = NULL; |
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goto out; |
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} |
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copy_destructor = gso_skb->destructor == tcp_wfree; |
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ooo_okay = gso_skb->ooo_okay; |
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/* All segments but the first should have ooo_okay cleared */ |
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skb->ooo_okay = 0; |
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segs = skb_segment(skb, features); |
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if (IS_ERR(segs)) |
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goto out; |
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/* Only first segment might have ooo_okay set */ |
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segs->ooo_okay = ooo_okay; |
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/* GSO partial and frag_list segmentation only requires splitting |
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* the frame into an MSS multiple and possibly a remainder, both |
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* cases return a GSO skb. So update the mss now. |
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*/ |
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if (skb_is_gso(segs)) |
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mss *= skb_shinfo(segs)->gso_segs; |
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delta = htonl(oldlen + (thlen + mss)); |
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skb = segs; |
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th = tcp_hdr(skb); |
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seq = ntohl(th->seq); |
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if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP)) |
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tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss); |
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newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + |
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(__force u32)delta)); |
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while (skb->next) { |
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th->fin = th->psh = 0; |
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th->check = newcheck; |
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if (skb->ip_summed == CHECKSUM_PARTIAL) |
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gso_reset_checksum(skb, ~th->check); |
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else |
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th->check = gso_make_checksum(skb, ~th->check); |
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seq += mss; |
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if (copy_destructor) { |
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skb->destructor = gso_skb->destructor; |
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skb->sk = gso_skb->sk; |
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sum_truesize += skb->truesize; |
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} |
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skb = skb->next; |
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th = tcp_hdr(skb); |
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th->seq = htonl(seq); |
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th->cwr = 0; |
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} |
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/* Following permits TCP Small Queues to work well with GSO : |
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* The callback to TCP stack will be called at the time last frag |
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* is freed at TX completion, and not right now when gso_skb |
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* is freed by GSO engine |
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*/ |
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if (copy_destructor) { |
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int delta; |
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swap(gso_skb->sk, skb->sk); |
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swap(gso_skb->destructor, skb->destructor); |
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sum_truesize += skb->truesize; |
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delta = sum_truesize - gso_skb->truesize; |
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/* In some pathological cases, delta can be negative. |
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* We need to either use refcount_add() or refcount_sub_and_test() |
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*/ |
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if (likely(delta >= 0)) |
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refcount_add(delta, &skb->sk->sk_wmem_alloc); |
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else |
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WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc)); |
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} |
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delta = htonl(oldlen + (skb_tail_pointer(skb) - |
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skb_transport_header(skb)) + |
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skb->data_len); |
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th->check = ~csum_fold((__force __wsum)((__force u32)th->check + |
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(__force u32)delta)); |
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if (skb->ip_summed == CHECKSUM_PARTIAL) |
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gso_reset_checksum(skb, ~th->check); |
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else |
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th->check = gso_make_checksum(skb, ~th->check); |
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out: |
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return segs; |
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} |
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struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) |
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{ |
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struct sk_buff *pp = NULL; |
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struct sk_buff *p; |
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struct tcphdr *th; |
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struct tcphdr *th2; |
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unsigned int len; |
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unsigned int thlen; |
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__be32 flags; |
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unsigned int mss = 1; |
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unsigned int hlen; |
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unsigned int off; |
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int flush = 1; |
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int i; |
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off = skb_gro_offset(skb); |
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hlen = off + sizeof(*th); |
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th = skb_gro_header_fast(skb, off); |
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if (skb_gro_header_hard(skb, hlen)) { |
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th = skb_gro_header_slow(skb, hlen, off); |
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if (unlikely(!th)) |
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goto out; |
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} |
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thlen = th->doff * 4; |
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if (thlen < sizeof(*th)) |
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goto out; |
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hlen = off + thlen; |
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if (skb_gro_header_hard(skb, hlen)) { |
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th = skb_gro_header_slow(skb, hlen, off); |
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if (unlikely(!th)) |
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goto out; |
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} |
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skb_gro_pull(skb, thlen); |
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len = skb_gro_len(skb); |
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flags = tcp_flag_word(th); |
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list_for_each_entry(p, head, list) { |
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if (!NAPI_GRO_CB(p)->same_flow) |
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continue; |
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th2 = tcp_hdr(p); |
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if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { |
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NAPI_GRO_CB(p)->same_flow = 0; |
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continue; |
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} |
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goto found; |
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} |
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p = NULL; |
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goto out_check_final; |
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found: |
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/* Include the IP ID check below from the inner most IP hdr */ |
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flush = NAPI_GRO_CB(p)->flush; |
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flush |= (__force int)(flags & TCP_FLAG_CWR); |
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flush |= (__force int)((flags ^ tcp_flag_word(th2)) & |
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~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); |
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flush |= (__force int)(th->ack_seq ^ th2->ack_seq); |
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for (i = sizeof(*th); i < thlen; i += 4) |
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flush |= *(u32 *)((u8 *)th + i) ^ |
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*(u32 *)((u8 *)th2 + i); |
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/* When we receive our second frame we can made a decision on if we |
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* continue this flow as an atomic flow with a fixed ID or if we use |
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* an incrementing ID. |
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*/ |
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if (NAPI_GRO_CB(p)->flush_id != 1 || |
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NAPI_GRO_CB(p)->count != 1 || |
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!NAPI_GRO_CB(p)->is_atomic) |
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flush |= NAPI_GRO_CB(p)->flush_id; |
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else |
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NAPI_GRO_CB(p)->is_atomic = false; |
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mss = skb_shinfo(p)->gso_size; |
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flush |= (len - 1) >= mss; |
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flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); |
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#ifdef CONFIG_TLS_DEVICE |
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flush |= p->decrypted ^ skb->decrypted; |
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#endif |
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if (flush || skb_gro_receive(p, skb)) { |
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mss = 1; |
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goto out_check_final; |
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} |
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tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); |
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out_check_final: |
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flush = len < mss; |
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flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | |
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TCP_FLAG_RST | TCP_FLAG_SYN | |
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TCP_FLAG_FIN)); |
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if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) |
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pp = p; |
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out: |
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NAPI_GRO_CB(skb)->flush |= (flush != 0); |
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return pp; |
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} |
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int tcp_gro_complete(struct sk_buff *skb) |
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{ |
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struct tcphdr *th = tcp_hdr(skb); |
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skb->csum_start = (unsigned char *)th - skb->head; |
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skb->csum_offset = offsetof(struct tcphdr, check); |
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skb->ip_summed = CHECKSUM_PARTIAL; |
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skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; |
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if (th->cwr) |
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skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; |
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if (skb->encapsulation) |
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skb->inner_transport_header = skb->transport_header; |
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return 0; |
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} |
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EXPORT_SYMBOL(tcp_gro_complete); |
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INDIRECT_CALLABLE_SCOPE |
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struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb) |
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{ |
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/* Don't bother verifying checksum if we're going to flush anyway. */ |
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if (!NAPI_GRO_CB(skb)->flush && |
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skb_gro_checksum_validate(skb, IPPROTO_TCP, |
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inet_gro_compute_pseudo)) { |
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NAPI_GRO_CB(skb)->flush = 1; |
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return NULL; |
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} |
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return tcp_gro_receive(head, skb); |
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} |
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INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
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{ |
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const struct iphdr *iph = ip_hdr(skb); |
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struct tcphdr *th = tcp_hdr(skb); |
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th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, |
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iph->daddr, 0); |
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skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; |
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if (NAPI_GRO_CB(skb)->is_atomic) |
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skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; |
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return tcp_gro_complete(skb); |
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} |
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static const struct net_offload tcpv4_offload = { |
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.callbacks = { |
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.gso_segment = tcp4_gso_segment, |
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.gro_receive = tcp4_gro_receive, |
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.gro_complete = tcp4_gro_complete, |
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}, |
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}; |
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int __init tcpv4_offload_init(void) |
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{ |
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return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); |
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}
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