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net/ipv4/tcp_offload.c
8.13 KB
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* * IPV4 GSO/GRO offload support * Linux INET implementation * |
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* TCPv4 GSO/GRO support */ |
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#include <linux/indirect_call_wrapper.h> |
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#include <linux/skbuff.h> #include <net/tcp.h> #include <net/protocol.h> |
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static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq, unsigned int seq, unsigned int mss) |
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{ while (skb) { |
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if (before(ts_seq, seq + mss)) { skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP; |
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skb_shinfo(skb)->tskey = ts_seq; return; } skb = skb->next; seq += mss; } } |
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static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb, netdev_features_t features) |
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{ |
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)) return ERR_PTR(-EINVAL); |
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if (!pskb_may_pull(skb, sizeof(struct tcphdr))) return ERR_PTR(-EINVAL); if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) { const struct iphdr *iph = ip_hdr(skb); struct tcphdr *th = tcp_hdr(skb); /* Set up checksum pseudo header, usually expect stack to * have done this already. */ th->check = 0; skb->ip_summed = CHECKSUM_PARTIAL; __tcp_v4_send_check(skb, iph->saddr, iph->daddr); } return tcp_gso_segment(skb, features); } |
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struct sk_buff *tcp_gso_segment(struct sk_buff *skb, |
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netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); |
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unsigned int sum_truesize = 0; |
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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; |
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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); |
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mss = skb_shinfo(skb)->gso_size; |
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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. */ |
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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; |
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/* 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; |
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delta = htonl(oldlen + (thlen + mss)); skb = segs; th = tcp_hdr(skb); seq = ntohl(th->seq); |
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if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP)) tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss); |
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newcheck = ~csum_fold((__force __wsum)((__force u32)th->check + (__force u32)delta)); |
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while (skb->next) { |
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th->fin = th->psh = 0; th->check = newcheck; |
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if (skb->ip_summed == CHECKSUM_PARTIAL) gso_reset_checksum(skb, ~th->check); else |
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th->check = gso_make_checksum(skb, ~th->check); |
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seq += mss; if (copy_destructor) { skb->destructor = gso_skb->destructor; skb->sk = gso_skb->sk; |
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sum_truesize += skb->truesize; |
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} skb = skb->next; th = tcp_hdr(skb); th->seq = htonl(seq); th->cwr = 0; |
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} |
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/* 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) { |
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int delta; |
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swap(gso_skb->sk, skb->sk); swap(gso_skb->destructor, skb->destructor); |
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sum_truesize += skb->truesize; |
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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, &skb->sk->sk_wmem_alloc); else WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc)); |
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} 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)); |
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if (skb->ip_summed == CHECKSUM_PARTIAL) gso_reset_checksum(skb, ~th->check); else |
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th->check = gso_make_checksum(skb, ~th->check); |
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out: return segs; } |
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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; struct tcphdr *th; struct tcphdr *th2; unsigned int len; unsigned int thlen; __be32 flags; unsigned int mss = 1; unsigned int hlen; unsigned int off; int flush = 1; int i; off = skb_gro_offset(skb); hlen = off + sizeof(*th); th = skb_gro_header_fast(skb, off); if (skb_gro_header_hard(skb, hlen)) { th = skb_gro_header_slow(skb, hlen, off); if (unlikely(!th)) goto out; } thlen = th->doff * 4; if (thlen < sizeof(*th)) goto out; hlen = off + thlen; if (skb_gro_header_hard(skb, hlen)) { th = skb_gro_header_slow(skb, hlen, off); if (unlikely(!th)) goto out; } skb_gro_pull(skb, thlen); len = skb_gro_len(skb); 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) continue; th2 = tcp_hdr(p); if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { NAPI_GRO_CB(p)->same_flow = 0; continue; } goto found; } |
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p = NULL; |
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goto out_check_final; 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); flush |= (__force int)((flags ^ tcp_flag_word(th2)) & ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); flush |= (__force int)(th->ack_seq ^ th2->ack_seq); for (i = sizeof(*th); i < thlen; i += 4) flush |= *(u32 *)((u8 *)th + i) ^ *(u32 *)((u8 *)th2 + i); |
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/* When we receive our second frame we can made a decision on if we * continue this flow as an atomic flow with a fixed ID or if we use * an incrementing ID. */ if (NAPI_GRO_CB(p)->flush_id != 1 || NAPI_GRO_CB(p)->count != 1 || !NAPI_GRO_CB(p)->is_atomic) flush |= NAPI_GRO_CB(p)->flush_id; else 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; flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); |
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#ifdef CONFIG_TLS_DEVICE flush |= p->decrypted ^ skb->decrypted; #endif |
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if (flush || skb_gro_receive(p, skb)) { |
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mss = 1; goto out_check_final; } |
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tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); out_check_final: flush = len < mss; flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST | TCP_FLAG_SYN | TCP_FLAG_FIN)); 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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int tcp_gro_complete(struct sk_buff *skb) { 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); skb->ip_summed = CHECKSUM_PARTIAL; skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; if (th->cwr) skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; return 0; } EXPORT_SYMBOL(tcp_gro_complete); |
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INDIRECT_CALLABLE_SCOPE 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 && skb_gro_checksum_validate(skb, IPPROTO_TCP, inet_gro_compute_pseudo)) { |
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NAPI_GRO_CB(skb)->flush = 1; return NULL; |
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} return tcp_gro_receive(head, skb); } |
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INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff) |
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{ const struct iphdr *iph = ip_hdr(skb); struct tcphdr *th = tcp_hdr(skb); |
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th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, 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) skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; |
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return tcp_gro_complete(skb); } static const struct net_offload tcpv4_offload = { .callbacks = { |
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.gso_segment = tcp4_gso_segment, |
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.gro_receive = tcp4_gro_receive, .gro_complete = tcp4_gro_complete, }, }; int __init tcpv4_offload_init(void) { return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); } |