diff options
Diffstat (limited to 'net/ipv4/udp_offload.c')
| -rw-r--r-- | net/ipv4/udp_offload.c | 751 |
1 files changed, 751 insertions, 0 deletions
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c new file mode 100644 index 0000000000..6c95d28d0c --- /dev/null +++ b/net/ipv4/udp_offload.c @@ -0,0 +1,751 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IPV4 GSO/GRO offload support + * Linux INET implementation + * + * UDPv4 GSO support + */ + +#include <linux/skbuff.h> +#include <net/gro.h> +#include <net/gso.h> +#include <net/udp.h> +#include <net/protocol.h> +#include <net/inet_common.h> + +static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, + netdev_features_t features, + struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, + netdev_features_t features), + __be16 new_protocol, bool is_ipv6) +{ + int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); + bool remcsum, need_csum, offload_csum, gso_partial; + struct sk_buff *segs = ERR_PTR(-EINVAL); + struct udphdr *uh = udp_hdr(skb); + u16 mac_offset = skb->mac_header; + __be16 protocol = skb->protocol; + u16 mac_len = skb->mac_len; + int udp_offset, outer_hlen; + __wsum partial; + bool need_ipsec; + + if (unlikely(!pskb_may_pull(skb, tnl_hlen))) + goto out; + + /* Adjust partial header checksum to negate old length. + * We cannot rely on the value contained in uh->len as it is + * possible that the actual value exceeds the boundaries of the + * 16 bit length field due to the header being added outside of an + * IP or IPv6 frame that was already limited to 64K - 1. + */ + if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) + partial = (__force __wsum)uh->len; + else + partial = (__force __wsum)htonl(skb->len); + partial = csum_sub(csum_unfold(uh->check), partial); + + /* setup inner skb. */ + skb->encapsulation = 0; + SKB_GSO_CB(skb)->encap_level = 0; + __skb_pull(skb, tnl_hlen); + skb_reset_mac_header(skb); + skb_set_network_header(skb, skb_inner_network_offset(skb)); + skb_set_transport_header(skb, skb_inner_transport_offset(skb)); + skb->mac_len = skb_inner_network_offset(skb); + skb->protocol = new_protocol; + + need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM); + skb->encap_hdr_csum = need_csum; + + remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM); + skb->remcsum_offload = remcsum; + + need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb)); + /* Try to offload checksum if possible */ + offload_csum = !!(need_csum && + !need_ipsec && + (skb->dev->features & + (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) : + (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM)))); + + features &= skb->dev->hw_enc_features; + if (need_csum) + features &= ~NETIF_F_SCTP_CRC; + + /* The only checksum offload we care about from here on out is the + * outer one so strip the existing checksum feature flags and + * instead set the flag based on our outer checksum offload value. + */ + if (remcsum) { + features &= ~NETIF_F_CSUM_MASK; + if (!need_csum || offload_csum) + features |= NETIF_F_HW_CSUM; + } + + /* segment inner packet. */ + segs = gso_inner_segment(skb, features); + if (IS_ERR_OR_NULL(segs)) { + skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, + mac_len); + goto out; + } + + gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); + + outer_hlen = skb_tnl_header_len(skb); + udp_offset = outer_hlen - tnl_hlen; + skb = segs; + do { + unsigned int len; + + if (remcsum) + skb->ip_summed = CHECKSUM_NONE; + + /* Set up inner headers if we are offloading inner checksum */ + if (skb->ip_summed == CHECKSUM_PARTIAL) { + skb_reset_inner_headers(skb); + skb->encapsulation = 1; + } + + skb->mac_len = mac_len; + skb->protocol = protocol; + + __skb_push(skb, outer_hlen); + skb_reset_mac_header(skb); + skb_set_network_header(skb, mac_len); + skb_set_transport_header(skb, udp_offset); + len = skb->len - udp_offset; + uh = udp_hdr(skb); + + /* If we are only performing partial GSO the inner header + * will be using a length value equal to only one MSS sized + * segment instead of the entire frame. + */ + if (gso_partial && skb_is_gso(skb)) { + uh->len = htons(skb_shinfo(skb)->gso_size + + SKB_GSO_CB(skb)->data_offset + + skb->head - (unsigned char *)uh); + } else { + uh->len = htons(len); + } + + if (!need_csum) + continue; + + uh->check = ~csum_fold(csum_add(partial, + (__force __wsum)htonl(len))); + + if (skb->encapsulation || !offload_csum) { + uh->check = gso_make_checksum(skb, ~uh->check); + if (uh->check == 0) + uh->check = CSUM_MANGLED_0; + } else { + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = offsetof(struct udphdr, check); + } + } while ((skb = skb->next)); +out: + return segs; +} + +struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, + netdev_features_t features, + bool is_ipv6) +{ + const struct net_offload __rcu **offloads; + __be16 protocol = skb->protocol; + const struct net_offload *ops; + struct sk_buff *segs = ERR_PTR(-EINVAL); + struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, + netdev_features_t features); + + rcu_read_lock(); + + switch (skb->inner_protocol_type) { + case ENCAP_TYPE_ETHER: + protocol = skb->inner_protocol; + gso_inner_segment = skb_mac_gso_segment; + break; + case ENCAP_TYPE_IPPROTO: + offloads = is_ipv6 ? inet6_offloads : inet_offloads; + ops = rcu_dereference(offloads[skb->inner_ipproto]); + if (!ops || !ops->callbacks.gso_segment) + goto out_unlock; + gso_inner_segment = ops->callbacks.gso_segment; + break; + default: + goto out_unlock; + } + + segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, + protocol, is_ipv6); + +out_unlock: + rcu_read_unlock(); + + return segs; +} +EXPORT_SYMBOL(skb_udp_tunnel_segment); + +static void __udpv4_gso_segment_csum(struct sk_buff *seg, + __be32 *oldip, __be32 *newip, + __be16 *oldport, __be16 *newport) +{ + struct udphdr *uh; + struct iphdr *iph; + + if (*oldip == *newip && *oldport == *newport) + return; + + uh = udp_hdr(seg); + iph = ip_hdr(seg); + + if (uh->check) { + inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip, + true); + inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport, + false); + if (!uh->check) + uh->check = CSUM_MANGLED_0; + } + *oldport = *newport; + + csum_replace4(&iph->check, *oldip, *newip); + *oldip = *newip; +} + +static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs) +{ + struct sk_buff *seg; + struct udphdr *uh, *uh2; + struct iphdr *iph, *iph2; + + seg = segs; + uh = udp_hdr(seg); + iph = ip_hdr(seg); + + if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) && + (udp_hdr(seg)->source == udp_hdr(seg->next)->source) && + (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) && + (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr)) + return segs; + + while ((seg = seg->next)) { + uh2 = udp_hdr(seg); + iph2 = ip_hdr(seg); + + __udpv4_gso_segment_csum(seg, + &iph2->saddr, &iph->saddr, + &uh2->source, &uh->source); + __udpv4_gso_segment_csum(seg, + &iph2->daddr, &iph->daddr, + &uh2->dest, &uh->dest); + } + + return segs; +} + +static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb, + netdev_features_t features, + bool is_ipv6) +{ + unsigned int mss = skb_shinfo(skb)->gso_size; + + skb = skb_segment_list(skb, features, skb_mac_header_len(skb)); + if (IS_ERR(skb)) + return skb; + + udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss); + + return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb); +} + +struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, + netdev_features_t features, bool is_ipv6) +{ + struct sock *sk = gso_skb->sk; + unsigned int sum_truesize = 0; + struct sk_buff *segs, *seg; + struct udphdr *uh; + unsigned int mss; + bool copy_dtor; + __sum16 check; + __be16 newlen; + + mss = skb_shinfo(gso_skb)->gso_size; + if (gso_skb->len <= sizeof(*uh) + mss) + return ERR_PTR(-EINVAL); + + if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) { + /* Packet is from an untrusted source, reset gso_segs. */ + skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh), + mss); + return NULL; + } + + if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) + return __udp_gso_segment_list(gso_skb, features, is_ipv6); + + skb_pull(gso_skb, sizeof(*uh)); + + /* clear destructor to avoid skb_segment assigning it to tail */ + copy_dtor = gso_skb->destructor == sock_wfree; + if (copy_dtor) + gso_skb->destructor = NULL; + + segs = skb_segment(gso_skb, features); + if (IS_ERR_OR_NULL(segs)) { + if (copy_dtor) + gso_skb->destructor = sock_wfree; + return segs; + } + + /* 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; + + seg = segs; + uh = udp_hdr(seg); + + /* preserve TX timestamp flags and TS key for first segment */ + skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey; + skb_shinfo(seg)->tx_flags |= + (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP); + + /* compute checksum adjustment based on old length versus new */ + newlen = htons(sizeof(*uh) + mss); + check = csum16_add(csum16_sub(uh->check, uh->len), newlen); + + for (;;) { + if (copy_dtor) { + seg->destructor = sock_wfree; + seg->sk = sk; + sum_truesize += seg->truesize; + } + + if (!seg->next) + break; + + uh->len = newlen; + uh->check = check; + + if (seg->ip_summed == CHECKSUM_PARTIAL) + gso_reset_checksum(seg, ~check); + else + uh->check = gso_make_checksum(seg, ~check) ? : + CSUM_MANGLED_0; + + seg = seg->next; + uh = udp_hdr(seg); + } + + /* last packet can be partial gso_size, account for that in checksum */ + newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) + + seg->data_len); + check = csum16_add(csum16_sub(uh->check, uh->len), newlen); + + uh->len = newlen; + uh->check = check; + + if (seg->ip_summed == CHECKSUM_PARTIAL) + gso_reset_checksum(seg, ~check); + else + uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0; + + /* update refcount for the packet */ + if (copy_dtor) { + int 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, &sk->sk_wmem_alloc); + else + WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); + } + return segs; +} +EXPORT_SYMBOL_GPL(__udp_gso_segment); + +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; + __wsum csum; + struct udphdr *uh; + struct iphdr *iph; + + if (skb->encapsulation && + (skb_shinfo(skb)->gso_type & + (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { + segs = skb_udp_tunnel_segment(skb, features, false); + goto out; + } + + if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) + goto out; + + if (!pskb_may_pull(skb, sizeof(struct udphdr))) + goto out; + + if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) + return __udp_gso_segment(skb, features, false); + + mss = skb_shinfo(skb)->gso_size; + if (unlikely(skb->len <= mss)) + 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); + iph = ip_hdr(skb); + + uh->check = 0; + csum = skb_checksum(skb, 0, skb->len, 0); + uh->check = udp_v4_check(skb->len, iph->saddr, iph->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; + + /* Fragment the skb. IP headers of the fragments are updated in + * inet_gso_segment() + */ + segs = skb_segment(skb, features); +out: + return segs; +} + +static int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb) +{ + if (unlikely(p->len + skb->len >= 65536)) + return -E2BIG; + + if (NAPI_GRO_CB(p)->last == p) + skb_shinfo(p)->frag_list = skb; + else + NAPI_GRO_CB(p)->last->next = skb; + + skb_pull(skb, skb_gro_offset(skb)); + + NAPI_GRO_CB(p)->last = skb; + NAPI_GRO_CB(p)->count++; + p->data_len += skb->len; + + /* sk owenrship - if any - completely transferred to the aggregated packet */ + skb->destructor = NULL; + p->truesize += skb->truesize; + p->len += skb->len; + + NAPI_GRO_CB(skb)->same_flow = 1; + + return 0; +} + + +#define UDP_GRO_CNT_MAX 64 +static struct sk_buff *udp_gro_receive_segment(struct list_head *head, + struct sk_buff *skb) +{ + struct udphdr *uh = udp_gro_udphdr(skb); + struct sk_buff *pp = NULL; + struct udphdr *uh2; + struct sk_buff *p; + unsigned int ulen; + int ret = 0; + + /* requires non zero csum, for symmetry with GSO */ + if (!uh->check) { + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + + /* Do not deal with padded or malicious packets, sorry ! */ + ulen = ntohs(uh->len); + if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) { + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + /* pull encapsulating udp header */ + skb_gro_pull(skb, sizeof(struct udphdr)); + + list_for_each_entry(p, head, list) { + if (!NAPI_GRO_CB(p)->same_flow) + continue; + + uh2 = udp_hdr(p); + + /* Match ports only, as csum is always non zero */ + if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + + if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) { + NAPI_GRO_CB(skb)->flush = 1; + return p; + } + + /* Terminate the flow on len mismatch or if it grow "too much". + * Under small packet flood GRO count could elsewhere grow a lot + * leading to excessive truesize values. + * On len mismatch merge the first packet shorter than gso_size, + * otherwise complete the GRO packet. + */ + if (ulen > ntohs(uh2->len)) { + pp = p; + } else { + if (NAPI_GRO_CB(skb)->is_flist) { + if (!pskb_may_pull(skb, skb_gro_offset(skb))) { + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + if ((skb->ip_summed != p->ip_summed) || + (skb->csum_level != p->csum_level)) { + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + ret = skb_gro_receive_list(p, skb); + } else { + skb_gro_postpull_rcsum(skb, uh, + sizeof(struct udphdr)); + + ret = skb_gro_receive(p, skb); + } + } + + if (ret || ulen != ntohs(uh2->len) || + NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX) + pp = p; + + return pp; + } + + /* mismatch, but we never need to flush */ + return NULL; +} + +struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, + struct udphdr *uh, struct sock *sk) +{ + struct sk_buff *pp = NULL; + struct sk_buff *p; + struct udphdr *uh2; + unsigned int off = skb_gro_offset(skb); + int flush = 1; + + /* we can do L4 aggregation only if the packet can't land in a tunnel + * otherwise we could corrupt the inner stream + */ + NAPI_GRO_CB(skb)->is_flist = 0; + if (!sk || !udp_sk(sk)->gro_receive) { + if (skb->dev->features & NETIF_F_GRO_FRAGLIST) + NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1; + + if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) || + (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist) + return call_gro_receive(udp_gro_receive_segment, head, skb); + + /* no GRO, be sure flush the current packet */ + goto out; + } + + if (NAPI_GRO_CB(skb)->encap_mark || + (uh->check && skb->ip_summed != CHECKSUM_PARTIAL && + NAPI_GRO_CB(skb)->csum_cnt == 0 && + !NAPI_GRO_CB(skb)->csum_valid)) + goto out; + + /* mark that this skb passed once through the tunnel gro layer */ + NAPI_GRO_CB(skb)->encap_mark = 1; + + flush = 0; + + list_for_each_entry(p, head, list) { + if (!NAPI_GRO_CB(p)->same_flow) + continue; + + uh2 = (struct udphdr *)(p->data + off); + + /* Match ports and either checksums are either both zero + * or nonzero. + */ + if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || + (!uh->check ^ !uh2->check)) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + } + + skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ + skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); + pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); + +out: + skb_gro_flush_final(skb, pp, flush); + return pp; +} +EXPORT_SYMBOL(udp_gro_receive); + +static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport, + __be16 dport) +{ + const struct iphdr *iph = skb_gro_network_header(skb); + struct net *net = dev_net(skb->dev); + int iif, sdif; + + inet_get_iif_sdif(skb, &iif, &sdif); + + return __udp4_lib_lookup(net, iph->saddr, sport, + iph->daddr, dport, iif, + sdif, net->ipv4.udp_table, NULL); +} + +INDIRECT_CALLABLE_SCOPE +struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) +{ + struct udphdr *uh = udp_gro_udphdr(skb); + struct sock *sk = NULL; + struct sk_buff *pp; + + if (unlikely(!uh)) + goto flush; + + /* Don't bother verifying checksum if we're going to flush anyway. */ + if (NAPI_GRO_CB(skb)->flush) + goto skip; + + if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, + inet_gro_compute_pseudo)) + goto flush; + else if (uh->check) + skb_gro_checksum_try_convert(skb, IPPROTO_UDP, + inet_gro_compute_pseudo); +skip: + NAPI_GRO_CB(skb)->is_ipv6 = 0; + + if (static_branch_unlikely(&udp_encap_needed_key)) + sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest); + + pp = udp_gro_receive(head, skb, uh, sk); + return pp; + +flush: + NAPI_GRO_CB(skb)->flush = 1; + return NULL; +} + +static int udp_gro_complete_segment(struct sk_buff *skb) +{ + struct udphdr *uh = udp_hdr(skb); + + skb->csum_start = (unsigned char *)uh - skb->head; + skb->csum_offset = offsetof(struct udphdr, check); + skb->ip_summed = CHECKSUM_PARTIAL; + + skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; + skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4; + + if (skb->encapsulation) + skb->inner_transport_header = skb->transport_header; + + return 0; +} + +int udp_gro_complete(struct sk_buff *skb, int nhoff, + udp_lookup_t lookup) +{ + __be16 newlen = htons(skb->len - nhoff); + struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); + struct sock *sk; + int err; + + uh->len = newlen; + + sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb, + udp4_lib_lookup_skb, skb, uh->source, uh->dest); + if (sk && udp_sk(sk)->gro_complete) { + skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM + : SKB_GSO_UDP_TUNNEL; + + /* clear the encap mark, so that inner frag_list gro_complete + * can take place + */ + NAPI_GRO_CB(skb)->encap_mark = 0; + + /* Set encapsulation before calling into inner gro_complete() + * functions to make them set up the inner offsets. + */ + skb->encapsulation = 1; + err = udp_sk(sk)->gro_complete(sk, skb, + nhoff + sizeof(struct udphdr)); + } else { + err = udp_gro_complete_segment(skb); + } + + if (skb->remcsum_offload) + skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; + + return err; +} +EXPORT_SYMBOL(udp_gro_complete); + +INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff) +{ + const struct iphdr *iph = ip_hdr(skb); + struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); + + /* do fraglist only if there is no outer UDP encap (or we already processed it) */ + if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) { + uh->len = htons(skb->len - nhoff); + + skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); + skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; + + if (skb->ip_summed == CHECKSUM_UNNECESSARY) { + if (skb->csum_level < SKB_MAX_CSUM_LEVEL) + skb->csum_level++; + } else { + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->csum_level = 0; + } + + return 0; + } + + if (uh->check) + uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, + iph->daddr, 0); + + return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb); +} + +static const struct net_offload udpv4_offload = { + .callbacks = { + .gso_segment = udp4_ufo_fragment, + .gro_receive = udp4_gro_receive, + .gro_complete = udp4_gro_complete, + }, +}; + +int __init udpv4_offload_init(void) +{ + return inet_add_offload(&udpv4_offload, IPPROTO_UDP); +} |