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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
xen-netback: add support for IPv6 checksum offload from guest
For performance of VM to VM traffic on a single host it is better to avoid calculation of TCP/UDP checksum in the sending frontend. To allow this this patch adds the code necessary to set up partial checksum for IPv6 packets and xenstore flag feature-ipv6-csum-offload to advertise that fact to frontends. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
146c8a77d2
commit
2eba61d55e
2 changed files with 222 additions and 56 deletions
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@ -109,15 +109,12 @@ static inline unsigned long idx_to_kaddr(struct xenvif *vif,
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return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
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}
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/*
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* This is the amount of packet we copy rather than map, so that the
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* guest can't fiddle with the contents of the headers while we do
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* packet processing on them (netfilter, routing, etc).
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/* This is a miniumum size for the linear area to avoid lots of
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* calls to __pskb_pull_tail() as we set up checksum offsets. The
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* value 128 was chosen as it covers all IPv4 and most likely
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* IPv6 headers.
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*/
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#define PKT_PROT_LEN (ETH_HLEN + \
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VLAN_HLEN + \
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sizeof(struct iphdr) + MAX_IPOPTLEN + \
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sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
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#define PKT_PROT_LEN 128
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static u16 frag_get_pending_idx(skb_frag_t *frag)
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{
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@ -1118,14 +1115,214 @@ static int xenvif_set_skb_gso(struct xenvif *vif,
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return 0;
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}
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static inline void maybe_pull_tail(struct sk_buff *skb, unsigned int len)
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{
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if (skb_is_nonlinear(skb) && skb_headlen(skb) < len) {
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/* If we need to pullup then pullup to the max, so we
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* won't need to do it again.
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*/
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int target = min_t(int, skb->len, MAX_TCP_HEADER);
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__pskb_pull_tail(skb, target - skb_headlen(skb));
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}
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}
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static int checksum_setup_ip(struct xenvif *vif, struct sk_buff *skb,
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int recalculate_partial_csum)
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{
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struct iphdr *iph = (void *)skb->data;
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unsigned int header_size;
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unsigned int off;
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int err = -EPROTO;
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off = sizeof(struct iphdr);
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header_size = skb->network_header + off + MAX_IPOPTLEN;
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maybe_pull_tail(skb, header_size);
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off = iph->ihl * 4;
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switch (iph->protocol) {
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case IPPROTO_TCP:
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if (!skb_partial_csum_set(skb, off,
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offsetof(struct tcphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct tcphdr *tcph = tcp_hdr(skb);
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header_size = skb->network_header +
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off +
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sizeof(struct tcphdr);
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maybe_pull_tail(skb, header_size);
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tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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skb->len - off,
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IPPROTO_TCP, 0);
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}
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break;
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case IPPROTO_UDP:
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if (!skb_partial_csum_set(skb, off,
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offsetof(struct udphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct udphdr *udph = udp_hdr(skb);
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header_size = skb->network_header +
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off +
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sizeof(struct udphdr);
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maybe_pull_tail(skb, header_size);
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udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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skb->len - off,
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IPPROTO_UDP, 0);
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}
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break;
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default:
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if (net_ratelimit())
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netdev_err(vif->dev,
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"Attempting to checksum a non-TCP/UDP packet, "
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"dropping a protocol %d packet\n",
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iph->protocol);
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goto out;
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}
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err = 0;
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out:
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return err;
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}
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static int checksum_setup_ipv6(struct xenvif *vif, struct sk_buff *skb,
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int recalculate_partial_csum)
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{
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int err = -EPROTO;
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struct ipv6hdr *ipv6h = (void *)skb->data;
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u8 nexthdr;
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unsigned int header_size;
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unsigned int off;
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bool fragment;
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bool done;
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done = false;
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off = sizeof(struct ipv6hdr);
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header_size = skb->network_header + off;
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maybe_pull_tail(skb, header_size);
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nexthdr = ipv6h->nexthdr;
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while ((off <= sizeof(struct ipv6hdr) + ntohs(ipv6h->payload_len)) &&
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!done) {
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switch (nexthdr) {
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case IPPROTO_DSTOPTS:
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case IPPROTO_HOPOPTS:
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case IPPROTO_ROUTING: {
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struct ipv6_opt_hdr *hp = (void *)(skb->data + off);
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header_size = skb->network_header +
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off +
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sizeof(struct ipv6_opt_hdr);
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maybe_pull_tail(skb, header_size);
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nexthdr = hp->nexthdr;
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off += ipv6_optlen(hp);
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break;
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}
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case IPPROTO_AH: {
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struct ip_auth_hdr *hp = (void *)(skb->data + off);
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header_size = skb->network_header +
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off +
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sizeof(struct ip_auth_hdr);
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maybe_pull_tail(skb, header_size);
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nexthdr = hp->nexthdr;
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off += (hp->hdrlen+2)<<2;
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break;
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}
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case IPPROTO_FRAGMENT:
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fragment = true;
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/* fall through */
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default:
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done = true;
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break;
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}
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}
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if (!done) {
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if (net_ratelimit())
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netdev_err(vif->dev, "Failed to parse packet header\n");
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goto out;
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}
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if (fragment) {
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if (net_ratelimit())
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netdev_err(vif->dev, "Packet is a fragment!\n");
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goto out;
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}
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switch (nexthdr) {
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case IPPROTO_TCP:
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if (!skb_partial_csum_set(skb, off,
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offsetof(struct tcphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct tcphdr *tcph = tcp_hdr(skb);
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header_size = skb->network_header +
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off +
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sizeof(struct tcphdr);
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maybe_pull_tail(skb, header_size);
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tcph->check = ~csum_ipv6_magic(&ipv6h->saddr,
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&ipv6h->daddr,
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skb->len - off,
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IPPROTO_TCP, 0);
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}
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break;
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case IPPROTO_UDP:
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if (!skb_partial_csum_set(skb, off,
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offsetof(struct udphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct udphdr *udph = udp_hdr(skb);
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header_size = skb->network_header +
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off +
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sizeof(struct udphdr);
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maybe_pull_tail(skb, header_size);
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udph->check = ~csum_ipv6_magic(&ipv6h->saddr,
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&ipv6h->daddr,
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skb->len - off,
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IPPROTO_UDP, 0);
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}
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break;
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default:
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if (net_ratelimit())
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netdev_err(vif->dev,
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"Attempting to checksum a non-TCP/UDP packet, "
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"dropping a protocol %d packet\n",
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nexthdr);
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goto out;
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}
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err = 0;
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out:
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return err;
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}
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static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
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{
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struct iphdr *iph;
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int err = -EPROTO;
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int recalculate_partial_csum = 0;
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/*
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* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
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/* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
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* peers can fail to set NETRXF_csum_blank when sending a GSO
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* frame. In this case force the SKB to CHECKSUM_PARTIAL and
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* recalculate the partial checksum.
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@ -1140,46 +1337,11 @@ static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
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if (skb->ip_summed != CHECKSUM_PARTIAL)
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return 0;
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if (skb->protocol != htons(ETH_P_IP))
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goto out;
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if (skb->protocol == htons(ETH_P_IP))
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err = checksum_setup_ip(vif, skb, recalculate_partial_csum);
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else if (skb->protocol == htons(ETH_P_IPV6))
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err = checksum_setup_ipv6(vif, skb, recalculate_partial_csum);
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iph = (void *)skb->data;
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switch (iph->protocol) {
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case IPPROTO_TCP:
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if (!skb_partial_csum_set(skb, 4 * iph->ihl,
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offsetof(struct tcphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct tcphdr *tcph = tcp_hdr(skb);
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tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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skb->len - iph->ihl*4,
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IPPROTO_TCP, 0);
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}
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break;
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case IPPROTO_UDP:
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if (!skb_partial_csum_set(skb, 4 * iph->ihl,
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offsetof(struct udphdr, check)))
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goto out;
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if (recalculate_partial_csum) {
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struct udphdr *udph = udp_hdr(skb);
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udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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skb->len - iph->ihl*4,
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IPPROTO_UDP, 0);
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}
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break;
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default:
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if (net_ratelimit())
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netdev_err(vif->dev,
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"Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
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iph->protocol);
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goto out;
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}
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err = 0;
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out:
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return err;
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}
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@ -1428,12 +1590,7 @@ static int xenvif_tx_submit(struct xenvif *vif, int budget)
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xenvif_fill_frags(vif, skb);
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/*
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* If the initial fragment was < PKT_PROT_LEN then
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* pull through some bytes from the other fragments to
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* increase the linear region to PKT_PROT_LEN bytes.
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*/
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if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
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if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
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int target = min_t(int, skb->len, PKT_PROT_LEN);
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__pskb_pull_tail(skb, target - skb_headlen(skb));
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}
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@ -105,6 +105,15 @@ static int netback_probe(struct xenbus_device *dev,
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goto abort_transaction;
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}
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/* We support partial checksum setup for IPv6 packets */
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err = xenbus_printf(xbt, dev->nodename,
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"feature-ipv6-csum-offload",
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"%d", 1);
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if (err) {
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message = "writing feature-ipv6-csum-offload";
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goto abort_transaction;
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}
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/* We support rx-copy path. */
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err = xenbus_printf(xbt, dev->nodename,
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"feature-rx-copy", "%d", 1);
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