From 28850dc7c71da9d0c0e39246e9ff6913f41f8d0a Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 7 Jun 2013 05:11:46 +0000 Subject: net: tcp: move GRO/GSO functions to tcp_offload Would be good to make things explicit and move those functions to a new file called tcp_offload.c, thus make this similar to tcpv6_offload.c. While moving all related functions into tcp_offload.c, we can also make some of them static, since they are only used there. Also, add an explicit registration function. Suggested-by: Eric Dumazet Signed-off-by: Daniel Borkmann Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_offload.c | 332 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 332 insertions(+) create mode 100644 net/ipv4/tcp_offload.c (limited to 'net/ipv4/tcp_offload.c') diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c new file mode 100644 index 000000000000..3a7525e6c086 --- /dev/null +++ b/net/ipv4/tcp_offload.c @@ -0,0 +1,332 @@ +/* + * IPV4 GSO/GRO offload support + * Linux INET implementation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * TCPv4 GSO/GRO support + */ + +#include +#include +#include + +struct sk_buff *tcp_tso_segment(struct sk_buff *skb, + netdev_features_t features) +{ + struct sk_buff *segs = ERR_PTR(-EINVAL); + 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_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; + /* {tcp|sock}_wfree() use exact truesize accounting : + * sum(skb->truesize) MUST be exactly be gso_skb->truesize + * So we account mss bytes of 'true size' for each segment. + * The last segment will contain the remaining. + */ + skb->truesize = mss; + gso_skb->truesize -= mss; + } + 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); + swap(gso_skb->truesize, skb->truesize); + } + + 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; +} +EXPORT_SYMBOL(tcp_tso_segment); + +struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + struct sk_buff **pp = NULL; + 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); + + for (; (p = *head); head = &p->next) { + 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; + } + + goto out_check_final; + +found: + flush = NAPI_GRO_CB(p)->flush; + 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); + + mss = tcp_skb_mss(p); + + flush |= (len - 1) >= mss; + flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); + + if (flush || skb_gro_receive(head, skb)) { + mss = 1; + goto out_check_final; + } + + p = *head; + th2 = tcp_hdr(p); + 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)) + pp = head; + +out: + NAPI_GRO_CB(skb)->flush |= flush; + + return pp; +} +EXPORT_SYMBOL(tcp_gro_receive); + +int tcp_gro_complete(struct sk_buff *skb) +{ + struct tcphdr *th = tcp_hdr(skb); + + skb->csum_start = skb_transport_header(skb) - skb->head; + 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); + +static int tcp_v4_gso_send_check(struct sk_buff *skb) +{ + const struct iphdr *iph; + struct tcphdr *th; + + if (!pskb_may_pull(skb, sizeof(*th))) + return -EINVAL; + + iph = ip_hdr(skb); + th = tcp_hdr(skb); + + th->check = 0; + skb->ip_summed = CHECKSUM_PARTIAL; + __tcp_v4_send_check(skb, iph->saddr, iph->daddr); + return 0; +} + +static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + const struct iphdr *iph = skb_gro_network_header(skb); + __wsum wsum; + __sum16 sum; + + switch (skb->ip_summed) { + case CHECKSUM_COMPLETE: + if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, + skb->csum)) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + break; + } +flush: + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + + case CHECKSUM_NONE: + wsum = csum_tcpudp_nofold(iph->saddr, iph->daddr, + skb_gro_len(skb), IPPROTO_TCP, 0); + sum = csum_fold(skb_checksum(skb, + skb_gro_offset(skb), + skb_gro_len(skb), + wsum)); + if (sum) + goto flush; + + skb->ip_summed = CHECKSUM_UNNECESSARY; + break; + } + + return tcp_gro_receive(head, skb); +} + +static int tcp4_gro_complete(struct sk_buff *skb) +{ + const struct iphdr *iph = ip_hdr(skb); + struct tcphdr *th = tcp_hdr(skb); + + th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb), + iph->saddr, iph->daddr, 0); + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; + + return tcp_gro_complete(skb); +} + +static const struct net_offload tcpv4_offload = { + .callbacks = { + .gso_send_check = tcp_v4_gso_send_check, + .gso_segment = tcp_tso_segment, + .gro_receive = tcp4_gro_receive, + .gro_complete = tcp4_gro_complete, + }, +}; + +int __init tcpv4_offload_init(void) +{ + return inet_add_offload(&tcpv4_offload, IPPROTO_TCP); +} -- cgit v1.2.3