From 07b26c9454a2a19fff86d6fcf2aba6bc801eb8d8 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Mon, 19 Sep 2016 12:58:47 +0200 Subject: [PATCH] gso: Support partial splitting at the frag_list pointer Since commit 8a29111c7 ("net: gro: allow to build full sized skb") gro may build buffers with a frag_list. This can hurt forwarding because most NICs can't offload such packets, they need to be segmented in software. This patch splits buffers with a frag_list at the frag_list pointer into buffers that can be TSO offloaded. Signed-off-by: Steffen Klassert Acked-by: Alexander Duyck Signed-off-by: David S. Miller --- net/core/skbuff.c | 51 +++++++++++++++++++++++++++++++++++++++----------- net/ipv4/af_inet.c | 14 ++++++++++---- net/ipv4/gre_offload.c | 6 ++++-- net/ipv4/tcp_offload.c | 13 +++++++------ net/ipv4/udp_offload.c | 6 ++++-- net/ipv6/ip6_offload.c | 5 ++++- 6 files changed, 69 insertions(+), 26 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 1e329d411242..7bf82a28e10a 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3097,11 +3097,31 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, sg = !!(features & NETIF_F_SG); csum = !!can_checksum_protocol(features, proto); - /* GSO partial only requires that we trim off any excess that - * doesn't fit into an MSS sized block, so take care of that - * now. - */ - if (sg && csum && (features & NETIF_F_GSO_PARTIAL)) { + if (sg && csum && (mss != GSO_BY_FRAGS)) { + if (!(features & NETIF_F_GSO_PARTIAL)) { + struct sk_buff *iter; + + if (!list_skb || + !net_gso_ok(features, skb_shinfo(head_skb)->gso_type)) + goto normal; + + /* Split the buffer at the frag_list pointer. + * This is based on the assumption that all + * buffers in the chain excluding the last + * containing the same amount of data. + */ + skb_walk_frags(head_skb, iter) { + if (skb_headlen(iter)) + goto normal; + + len -= iter->len; + } + } + + /* GSO partial only requires that we trim off any excess that + * doesn't fit into an MSS sized block, so take care of that + * now. + */ partial_segs = len / mss; if (partial_segs > 1) mss *= partial_segs; @@ -3109,6 +3129,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, partial_segs = 0; } +normal: headroom = skb_headroom(head_skb); pos = skb_headlen(head_skb); @@ -3300,21 +3321,29 @@ perform_csum_check: */ segs->prev = tail; - /* Update GSO info on first skb in partial sequence. */ if (partial_segs) { + struct sk_buff *iter; int type = skb_shinfo(head_skb)->gso_type; + unsigned short gso_size = skb_shinfo(head_skb)->gso_size; /* Update type to add partial and then remove dodgy if set */ - type |= SKB_GSO_PARTIAL; + type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL; type &= ~SKB_GSO_DODGY; /* Update GSO info and prepare to start updating headers on * our way back down the stack of protocols. */ - skb_shinfo(segs)->gso_size = skb_shinfo(head_skb)->gso_size; - skb_shinfo(segs)->gso_segs = partial_segs; - skb_shinfo(segs)->gso_type = type; - SKB_GSO_CB(segs)->data_offset = skb_headroom(segs) + doffset; + for (iter = segs; iter; iter = iter->next) { + skb_shinfo(iter)->gso_size = gso_size; + skb_shinfo(iter)->gso_segs = partial_segs; + skb_shinfo(iter)->gso_type = type; + SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset; + } + + if (tail->len - doffset <= gso_size) + skb_shinfo(tail)->gso_size = 0; + else if (tail != segs) + skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size); } /* Following permits correct backpressure, for protocols diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index e94b47be0019..1effc986739e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1192,7 +1192,7 @@ EXPORT_SYMBOL(inet_sk_rebuild_header); struct sk_buff *inet_gso_segment(struct sk_buff *skb, netdev_features_t features) { - bool udpfrag = false, fixedid = false, encap; + bool udpfrag = false, fixedid = false, gso_partial, encap; struct sk_buff *segs = ERR_PTR(-EINVAL); const struct net_offload *ops; unsigned int offset = 0; @@ -1245,6 +1245,8 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb, if (IS_ERR_OR_NULL(segs)) goto out; + gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); + skb = segs; do { iph = (struct iphdr *)(skb_mac_header(skb) + nhoff); @@ -1259,9 +1261,13 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb, iph->id = htons(id); id += skb_shinfo(skb)->gso_segs; } - tot_len = skb_shinfo(skb)->gso_size + - SKB_GSO_CB(skb)->data_offset + - skb->head - (unsigned char *)iph; + + if (gso_partial) + tot_len = skb_shinfo(skb)->gso_size + + SKB_GSO_CB(skb)->data_offset + + skb->head - (unsigned char *)iph; + else + tot_len = skb->len - nhoff; } else { if (!fixedid) iph->id = htons(id++); diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index ecd1e09dbbf1..96e0efecefa6 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -24,7 +24,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, __be16 protocol = skb->protocol; u16 mac_len = skb->mac_len; int gre_offset, outer_hlen; - bool need_csum, ufo; + bool need_csum, ufo, gso_partial; if (!skb->encapsulation) goto out; @@ -69,6 +69,8 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, goto out; } + gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); + outer_hlen = skb_tnl_header_len(skb); gre_offset = outer_hlen - tnl_hlen; skb = segs; @@ -96,7 +98,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, greh = (struct gre_base_hdr *)skb_transport_header(skb); pcsum = (__sum16 *)(greh + 1); - if (skb_is_gso(skb)) { + if (gso_partial) { unsigned int partial_adj; /* Adjust checksum to account for the fact that diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index 5c5964962d0c..bc68da38ea86 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -90,12 +90,6 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb, goto out; } - /* GSO partial only requires splitting the frame into an MSS - * multiple and possibly a remainder. So update the mss now. - */ - if (features & NETIF_F_GSO_PARTIAL) - mss = skb->len - (skb->len % mss); - copy_destructor = gso_skb->destructor == tcp_wfree; ooo_okay = gso_skb->ooo_okay; /* All segments but the first should have ooo_okay cleared */ @@ -108,6 +102,13 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb, /* 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 = htonl(oldlen + (thlen + mss)); skb = segs; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 81f253b6ff36..f9333c963607 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -21,7 +21,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, __be16 new_protocol, bool is_ipv6) { int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); - bool remcsum, need_csum, offload_csum, ufo; + bool remcsum, need_csum, offload_csum, ufo, gso_partial; struct sk_buff *segs = ERR_PTR(-EINVAL); struct udphdr *uh = udp_hdr(skb); u16 mac_offset = skb->mac_header; @@ -88,6 +88,8 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 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; @@ -117,7 +119,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, * will be using a length value equal to only one MSS sized * segment instead of the entire frame. */ - if (skb_is_gso(skb)) { + if (gso_partial) { uh->len = htons(skb_shinfo(skb)->gso_size + SKB_GSO_CB(skb)->data_offset + skb->head - (unsigned char *)uh); diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 22e90e56b5a9..e7bfd55899a3 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -69,6 +69,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int offset = 0; bool encap, udpfrag; int nhoff; + bool gso_partial; skb_reset_network_header(skb); nhoff = skb_network_header(skb) - skb_mac_header(skb); @@ -101,9 +102,11 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, if (IS_ERR(segs)) goto out; + gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); + for (skb = segs; skb; skb = skb->next) { ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); - if (skb_is_gso(skb)) + if (gso_partial) payload_len = skb_shinfo(skb)->gso_size + SKB_GSO_CB(skb)->data_offset + skb->head - (unsigned char *)(ipv6h + 1); -- 2.11.0