![Alexander Duyck](/assets/img/avatar_default.png)
This patch adds support for something I am referring to as GSO partial. The basic idea is that we can support a broader range of devices for segmentation if we use fixed outer headers and have the hardware only really deal with segmenting the inner header. The idea behind the naming is due to the fact that everything before csum_start will be fixed headers, and everything after will be the region that is handled by hardware. With the current implementation it allows us to add support for the following GSO types with an inner TSO_MANGLEID or TSO6 offload: NETIF_F_GSO_GRE NETIF_F_GSO_GRE_CSUM NETIF_F_GSO_IPIP NETIF_F_GSO_SIT NETIF_F_UDP_TUNNEL NETIF_F_UDP_TUNNEL_CSUM In the case of hardware that already supports tunneling we may be able to extend this further to support TSO_TCPV4 without TSO_MANGLEID if the hardware can support updating inner IPv4 headers. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
298 lines
7.3 KiB
C
298 lines
7.3 KiB
C
/*
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* IPV4 GSO/GRO offload support
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* Linux INET implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* GRE GSO support
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*/
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#include <linux/skbuff.h>
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#include <linux/init.h>
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#include <net/protocol.h>
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#include <net/gre.h>
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static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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u16 mac_offset = skb->mac_header;
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__be16 protocol = skb->protocol;
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u16 mac_len = skb->mac_len;
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int gre_offset, outer_hlen;
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bool need_csum, ufo;
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if (unlikely(skb_shinfo(skb)->gso_type &
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~(SKB_GSO_TCPV4 |
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SKB_GSO_TCPV6 |
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SKB_GSO_UDP |
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SKB_GSO_DODGY |
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SKB_GSO_TCP_ECN |
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SKB_GSO_TCP_FIXEDID |
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SKB_GSO_GRE |
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SKB_GSO_GRE_CSUM |
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SKB_GSO_IPIP |
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SKB_GSO_SIT |
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SKB_GSO_PARTIAL)))
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goto out;
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if (!skb->encapsulation)
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goto out;
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if (unlikely(tnl_hlen < sizeof(struct gre_base_hdr)))
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goto out;
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if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
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goto out;
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/* setup inner skb. */
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skb->encapsulation = 0;
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SKB_GSO_CB(skb)->encap_level = 0;
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__skb_pull(skb, tnl_hlen);
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, skb_inner_network_offset(skb));
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skb->mac_len = skb_inner_network_offset(skb);
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skb->protocol = skb->inner_protocol;
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need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM);
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skb->encap_hdr_csum = need_csum;
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ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
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features &= skb->dev->hw_enc_features;
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/* The only checksum offload we care about from here on out is the
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* outer one so strip the existing checksum feature flags based
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* on the fact that we will be computing our checksum in software.
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*/
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if (ufo) {
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features &= ~NETIF_F_CSUM_MASK;
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if (!need_csum)
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features |= NETIF_F_HW_CSUM;
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}
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/* segment inner packet. */
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segs = skb_mac_gso_segment(skb, features);
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if (IS_ERR_OR_NULL(segs)) {
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skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
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mac_len);
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goto out;
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}
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outer_hlen = skb_tnl_header_len(skb);
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gre_offset = outer_hlen - tnl_hlen;
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skb = segs;
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do {
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struct gre_base_hdr *greh;
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__sum16 *pcsum;
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/* Set up inner headers if we are offloading inner checksum */
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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skb_reset_inner_headers(skb);
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skb->encapsulation = 1;
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}
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skb->mac_len = mac_len;
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skb->protocol = protocol;
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__skb_push(skb, outer_hlen);
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, mac_len);
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skb_set_transport_header(skb, gre_offset);
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if (!need_csum)
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continue;
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greh = (struct gre_base_hdr *)skb_transport_header(skb);
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pcsum = (__sum16 *)(greh + 1);
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if (skb_is_gso(skb)) {
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unsigned int partial_adj;
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/* Adjust checksum to account for the fact that
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* the partial checksum is based on actual size
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* whereas headers should be based on MSS size.
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*/
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partial_adj = skb->len + skb_headroom(skb) -
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SKB_GSO_CB(skb)->data_offset -
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skb_shinfo(skb)->gso_size;
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*pcsum = ~csum_fold((__force __wsum)htonl(partial_adj));
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} else {
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*pcsum = 0;
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}
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*(pcsum + 1) = 0;
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*pcsum = gso_make_checksum(skb, 0);
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} while ((skb = skb->next));
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out:
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return segs;
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}
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static struct sk_buff **gre_gro_receive(struct sk_buff **head,
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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;
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const struct gre_base_hdr *greh;
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unsigned int hlen, grehlen;
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unsigned int off;
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int flush = 1;
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struct packet_offload *ptype;
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__be16 type;
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if (NAPI_GRO_CB(skb)->encap_mark)
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goto out;
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NAPI_GRO_CB(skb)->encap_mark = 1;
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off = skb_gro_offset(skb);
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hlen = off + sizeof(*greh);
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greh = skb_gro_header_fast(skb, off);
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if (skb_gro_header_hard(skb, hlen)) {
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greh = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!greh))
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goto out;
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}
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/* Only support version 0 and K (key), C (csum) flags. Note that
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* although the support for the S (seq#) flag can be added easily
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* for GRO, this is problematic for GSO hence can not be enabled
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* here because a GRO pkt may end up in the forwarding path, thus
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* requiring GSO support to break it up correctly.
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*/
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if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0)
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goto out;
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/* We can only support GRE_CSUM if we can track the location of
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* the GRE header. In the case of FOU/GUE we cannot because the
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* outer UDP header displaces the GRE header leaving us in a state
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* of limbo.
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*/
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if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou)
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goto out;
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type = greh->protocol;
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rcu_read_lock();
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ptype = gro_find_receive_by_type(type);
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if (!ptype)
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goto out_unlock;
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grehlen = GRE_HEADER_SECTION;
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if (greh->flags & GRE_KEY)
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grehlen += GRE_HEADER_SECTION;
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if (greh->flags & GRE_CSUM)
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grehlen += GRE_HEADER_SECTION;
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hlen = off + grehlen;
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if (skb_gro_header_hard(skb, hlen)) {
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greh = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!greh))
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goto out_unlock;
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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 ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) {
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if (skb_gro_checksum_simple_validate(skb))
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goto out_unlock;
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skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0,
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null_compute_pseudo);
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}
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for (p = *head; p; p = p->next) {
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const struct gre_base_hdr *greh2;
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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/* The following checks are needed to ensure only pkts
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* from the same tunnel are considered for aggregation.
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* The criteria for "the same tunnel" includes:
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* 1) same version (we only support version 0 here)
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* 2) same protocol (we only support ETH_P_IP for now)
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* 3) same set of flags
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* 4) same key if the key field is present.
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*/
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greh2 = (struct gre_base_hdr *)(p->data + off);
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if (greh2->flags != greh->flags ||
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greh2->protocol != greh->protocol) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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if (greh->flags & GRE_KEY) {
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/* compare keys */
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if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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}
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}
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skb_gro_pull(skb, grehlen);
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/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
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skb_gro_postpull_rcsum(skb, greh, grehlen);
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pp = ptype->callbacks.gro_receive(head, skb);
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flush = 0;
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out_unlock:
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rcu_read_unlock();
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out:
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NAPI_GRO_CB(skb)->flush |= flush;
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return pp;
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}
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static int gre_gro_complete(struct sk_buff *skb, int nhoff)
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{
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struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
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struct packet_offload *ptype;
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unsigned int grehlen = sizeof(*greh);
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int err = -ENOENT;
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__be16 type;
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type = SKB_GSO_GRE;
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type = greh->protocol;
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if (greh->flags & GRE_KEY)
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grehlen += GRE_HEADER_SECTION;
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if (greh->flags & GRE_CSUM)
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grehlen += GRE_HEADER_SECTION;
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rcu_read_lock();
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ptype = gro_find_complete_by_type(type);
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if (ptype)
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err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
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rcu_read_unlock();
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skb_set_inner_mac_header(skb, nhoff + grehlen);
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return err;
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}
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static const struct net_offload gre_offload = {
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.callbacks = {
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.gso_segment = gre_gso_segment,
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.gro_receive = gre_gro_receive,
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.gro_complete = gre_gro_complete,
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},
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};
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static int __init gre_offload_init(void)
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{
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return inet_add_offload(&gre_offload, IPPROTO_GRE);
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}
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device_initcall(gre_offload_init);
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