diff options
Diffstat (limited to '')
-rw-r--r-- | net/ipv4/tcp_offload.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c new file mode 100644 index 000000000..4851211aa --- /dev/null +++ b/net/ipv4/tcp_offload.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IPV4 GSO/GRO offload support + * Linux INET implementation + * + * TCPv4 GSO/GRO support + */ + +#include <linux/indirect_call_wrapper.h> +#include <linux/skbuff.h> +#include <net/gro.h> +#include <net/tcp.h> +#include <net/protocol.h> + +static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq, + unsigned int seq, unsigned int mss) +{ + while (skb) { + if (before(ts_seq, seq + mss)) { + skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP; + skb_shinfo(skb)->tskey = ts_seq; + return; + } + + skb = skb->next; + seq += mss; + } +} + +static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb, + netdev_features_t features) +{ + if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)) + return ERR_PTR(-EINVAL); + + 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); +} + +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; + unsigned int oldlen; + unsigned int mss; + struct sk_buff *gso_skb = skb; + __sum16 newcheck; + bool ooo_okay, copy_destructor; + __wsum delta; + + th = tcp_hdr(skb); + thlen = th->doff * 4; + if (thlen < sizeof(*th)) + goto out; + + if (!pskb_may_pull(skb, thlen)) + goto out; + + oldlen = ~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 = (__force __wsum)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(csum_add(csum_unfold(th->check), 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) { + int delta; + + swap(gso_skb->sk, skb->sk); + swap(gso_skb->destructor, skb->destructor); + sum_truesize += skb->truesize; + 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)); + } + + delta = (__force __wsum)htonl(oldlen + + (skb_tail_pointer(skb) - + skb_transport_header(skb)) + + skb->data_len); + th->check = ~csum_fold(csum_add(csum_unfold(th->check), 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; +} + +struct sk_buff *tcp_gro_receive(struct list_head *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(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); + + list_for_each_entry(p, head, list) { + 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; + } + p = NULL; + goto out_check_final; + +found: + /* Include the IP ID check below from the inner most IP hdr */ + 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); + + /* 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; + + mss = skb_shinfo(p)->gso_size; + + /* If skb is a GRO packet, make sure its gso_size matches prior packet mss. + * If it is a single frame, do not aggregate it if its length + * is bigger than our mss. + */ + if (unlikely(skb_is_gso(skb))) + flush |= (mss != skb_shinfo(skb)->gso_size); + else + flush |= (len - 1) >= mss; + + flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); +#ifdef CONFIG_TLS_DEVICE + flush |= p->decrypted ^ skb->decrypted; +#endif + + if (flush || skb_gro_receive(p, skb)) { + mss = 1; + goto out_check_final; + } + + tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); + +out_check_final: + /* Force a flush if last segment is smaller than mss. */ + if (unlikely(skb_is_gso(skb))) + flush = len != NAPI_GRO_CB(skb)->count * skb_shinfo(skb)->gso_size; + else + 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 = p; + +out: + NAPI_GRO_CB(skb)->flush |= (flush != 0); + + return pp; +} + +int tcp_gro_complete(struct sk_buff *skb) +{ + struct tcphdr *th = tcp_hdr(skb); + + skb->csum_start = (unsigned char *)th - 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; + + if (skb->encapsulation) + skb->inner_transport_header = skb->transport_header; + + return 0; +} +EXPORT_SYMBOL(tcp_gro_complete); + +INDIRECT_CALLABLE_SCOPE +struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb) +{ + /* Don't bother verifying checksum if we're going to flush anyway. */ + if (!NAPI_GRO_CB(skb)->flush && + skb_gro_checksum_validate(skb, IPPROTO_TCP, + inet_gro_compute_pseudo)) { + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + + return tcp_gro_receive(head, skb); +} + +INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff) +{ + const struct iphdr *iph = ip_hdr(skb); + struct tcphdr *th = tcp_hdr(skb); + + th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr, + iph->daddr, 0); + skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4; + + if (NAPI_GRO_CB(skb)->is_atomic) + skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID; + + return tcp_gro_complete(skb); +} + +static const struct net_offload tcpv4_offload = { + .callbacks = { + .gso_segment = tcp4_gso_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); +} |