Re: [Qemu-devel] [ RFC Patch v6 2/3] virtio-net rsc: support coalescing ipv6 tcp traffic

[Wei Xu <wexu@redhat.com>]

On 2016年05月30日 12:25, Jason Wang wrote:
>
>
> On 2016年05月29日 00:37, wexu@redhat.com wrote:
>> From: Wei Xu <wexu@redhat.com>
>>
>> Most stuffs are like ipv4 2 differences between ipv4 and ipv6.
>>
>> 1. Fragment length in ipv4 header includes itself, while it's not
>> included for ipv6, thus means ipv6 can carry a real '65535' payload.
>>
>> 2. IPv6 header does not need calculate header checksum.
>>
>> Signed-off-by: Wei Xu <wexu@redhat.com>
>> ---
>>   hw/net/virtio-net.c | 152
>> +++++++++++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 144 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>> index b3bb63b..cc8cbe4 100644
>> --- a/hw/net/virtio-net.c
>> +++ b/hw/net/virtio-net.c
>> @@ -53,6 +53,10 @@
>>   /* header length value in ip header without option */
>>   #define VIRTIO_NET_IP4_HEADER_LENGTH 5
>> +#define ETH_IP6_HDR_SZ (ETH_HDR_SZ + IP6_HDR_SZ)
>> +#define VIRTIO_NET_IP6_ADDR_SIZE   32      /* ipv6 saddr + daddr */
>> +#define VIRTIO_NET_MAX_IP6_PAYLOAD VIRTIO_NET_MAX_TCP_PAYLOAD
>> +
>>   /* Purge coalesced packets timer interval, This value affects the
>> performance
>>      a lot, and should be tuned carefully, '300000'(300us) is the
>> recommended
>>      value to pass the WHQL test, '50000' can gain 2x netperf
>> throughput with
>> @@ -1724,6 +1728,25 @@ static void
>> virtio_net_rsc_extract_unit4(NetRscChain *chain,
>>       unit->payload = htons(*unit->ip_plen) - ip_hdrlen -
>> unit->tcp_hdrlen;
>>   }
>> +static void virtio_net_rsc_extract_unit6(NetRscChain *chain,
>> +                                         const uint8_t *buf,
>> NetRscUnit* unit)
>> +{
>> +    uint16_t hdr_len;
>> +    struct ip6_header *ip6;
>> +
>> +    hdr_len = ((VirtIONet *)(chain->n))->guest_hdr_len;
>> +    ip6 = (struct ip6_header *)(buf + hdr_len + sizeof(struct
>> eth_header));
>> +    unit->ip = ip6;
>> +    unit->ip_plen = &(ip6->ip6_ctlun.ip6_un1.ip6_un1_plen);
>> +    unit->tcp = (struct tcp_header *)(((uint8_t *)unit->ip)\
>> +                                        + sizeof(struct ip6_header));
>> +    unit->tcp_hdrlen = (htons(unit->tcp->th_offset_flags) & 0xF000)
>> >> 10;
>> +
>> +    /* There is a difference between payload lenght in ipv4 and v6,
>> +       ip header is excluded in ipv6 */
>> +    unit->payload = htons(*unit->ip_plen) - unit->tcp_hdrlen;
>> +}
>> +
>>   static void virtio_net_rsc_ipv4_checksum(struct virtio_net_hdr *vhdr,
>>                                            struct ip_header *ip)
>>   {
>> @@ -1742,7 +1765,9 @@ static size_t
>> virtio_net_rsc_drain_seg(NetRscChain *chain, NetRscSeg *seg)
>>       struct virtio_net_hdr *h;
>>       h = (struct virtio_net_hdr *)seg->buf;
>> -    virtio_net_rsc_ipv4_checksum(h, seg->unit.ip);
>> +    if ((chain->proto == ETH_P_IP) && seg->is_coalesced) {
>> +        virtio_net_rsc_ipv4_checksum(h, seg->unit.ip);
>> +    }
>>       ret = virtio_net_do_receive(seg->nc, seg->buf, seg->size);
>>       QTAILQ_REMOVE(&chain->buffers, seg, next);
>>       g_free(seg->buf);
>> @@ -1798,7 +1823,7 @@ static void virtio_net_rsc_cache_buf(NetRscChain
>> *chain, NetClientState *nc,
>>       hdr_len = chain->n->guest_hdr_len;
>>       seg = g_malloc(sizeof(NetRscSeg));
>>       seg->buf = g_malloc(hdr_len + sizeof(struct eth_header)\
>> -                   + VIRTIO_NET_MAX_TCP_PAYLOAD);
>> +                   + sizeof(struct ip6_header) +
>> VIRTIO_NET_MAX_TCP_PAYLOAD);
>>       memcpy(seg->buf, buf, size);
>>       seg->size = size;
>>       seg->packets = 1;
>> @@ -1809,7 +1834,18 @@ static void
>> virtio_net_rsc_cache_buf(NetRscChain *chain, NetClientState *nc,
>>       QTAILQ_INSERT_TAIL(&chain->buffers, seg, next);
>>       chain->stat.cache++;
>> -    virtio_net_rsc_extract_unit4(chain, seg->buf, &seg->unit);
>> +    switch (chain->proto) {
>> +    case ETH_P_IP:
>> +        virtio_net_rsc_extract_unit4(chain, seg->buf, &seg->unit);
>> +        break;
>> +
>> +    case ETH_P_IPV6:
>> +        virtio_net_rsc_extract_unit6(chain, seg->buf, &seg->unit);
>> +        break;
>> +
>> +    default:
>> +        g_assert_not_reached();
>> +    }
>>   }
>>   static int32_t virtio_net_rsc_handle_ack(NetRscChain *chain,
>> @@ -1929,6 +1965,24 @@ static int32_t
>> virtio_net_rsc_coalesce4(NetRscChain *chain, NetRscSeg *seg,
>>       return virtio_net_rsc_coalesce_data(chain, seg, buf, unit);
>>   }
>> +static int32_t virtio_net_rsc_coalesce6(NetRscChain *chain, NetRscSeg
>> *seg,
>> +                        const uint8_t *buf, size_t size, NetRscUnit
>> *unit)
>> +{
>> +    struct ip6_header *ip1, *ip2;
>> +
>> +    ip1 = (struct ip6_header *)(unit->ip);
>> +    ip2 = (struct ip6_header *)(seg->unit.ip);
>> +    if (memcmp(&ip1->ip6_src, &ip2->ip6_src, sizeof(struct in6_address))
>> +        || memcmp(&ip1->ip6_dst, &ip2->ip6_dst, sizeof(struct
>> in6_address))
>> +        || (unit->tcp->th_sport ^ seg->unit.tcp->th_sport)
>> +        || (unit->tcp->th_dport ^ seg->unit.tcp->th_dport)) {
>> +            chain->stat.no_match++;
>> +            return RSC_NO_MATCH;
>> +    }
>> +
>> +    return virtio_net_rsc_coalesce_data(chain, seg, buf, unit);
>> +}
>> +
>>   /* Pakcets with 'SYN' should bypass, other flag should be sent after
>> drain
>>    * to prevent out of order */
>>   static int virtio_net_rsc_tcp_ctrl_check(NetRscChain *chain,
>> @@ -1981,7 +2035,11 @@ static size_t
>> virtio_net_rsc_do_coalesce(NetRscChain *chain, NetClientState *nc,
>>       NetRscSeg *seg, *nseg;
>>       QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, nseg) {
>> -        ret = virtio_net_rsc_coalesce4(chain, seg, buf, size, unit);
>> +        if (chain->proto == ETH_P_IP) {
>> +            ret = virtio_net_rsc_coalesce4(chain, seg, buf, size, unit);
>> +        } else {
>> +            ret = virtio_net_rsc_coalesce6(chain, seg, buf, size, unit);
>> +        }
>>           if (ret == RSC_FINAL) {
>>               if (virtio_net_rsc_drain_seg(chain, seg) == 0) {
>> @@ -2106,13 +2164,82 @@ static size_t
>> virtio_net_rsc_receive4(NetRscChain *chain, NetClientState* nc,
>>       return virtio_net_rsc_do_coalesce(chain, nc, buf, size, &unit);
>>   }
>> +static int32_t virtio_net_rsc_sanity_check6(NetRscChain *chain,
>> +                                            struct ip6_header *ip6,
>> +                                            const uint8_t *buf,
>> size_t size)
>> +{
>> +    uint16_t ip_len;
>> +    uint16_t hdr_len;
>> +
>> +    hdr_len = ((VirtIONet *)(chain->n))->guest_hdr_len;
>> +    if (size < (hdr_len + sizeof(struct eth_header) + sizeof(struct
>> ip6_header)
>> +        + sizeof(tcp_header))) {
>> +        return RSC_BYPASS;
>> +    }
>> +
>> +    if (((ip6->ip6_ctlun.ip6_un1.ip6_un1_flow & 0xF0) >> 4)
>> +        != IP_HEADER_VERSION_6) {
>> +        return RSC_BYPASS;
>> +    }
>> +
>> +    /* Both option and protocol is checked in this */
>> +    if (ip6->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_TCP) {
>> +        chain->stat.bypass_not_tcp++;
>> +        return RSC_BYPASS;
>> +    }
>> +
>> +    ip_len = htons(ip6->ip6_ctlun.ip6_un1.ip6_un1_plen);
>> +    if (ip_len < sizeof(struct tcp_header)
>> +        || ip_len > (size - hdr_len - sizeof(struct eth_header)
>> +                     - sizeof(struct ip6_header))) {
>> +        chain->stat.ip_hacked++;
>> +        return RSC_BYPASS;
>> +    }
>> +
>> +    return RSC_WANT;
>> +}
>> +
>> +static size_t virtio_net_rsc_receive6(void *opq, NetClientState* nc,
>> +                                      const uint8_t *buf, size_t size)
>> +{
>> +    int32_t ret;
>> +    uint16_t hdr_len;
>> +    NetRscChain *chain;
>> +    NetRscUnit unit;
>> +
>> +    chain = (NetRscChain *)opq;
>> +    hdr_len = ((VirtIONet *)(chain->n))->guest_hdr_len;
>> +    virtio_net_rsc_extract_unit6(chain, buf, &unit);
>
> Same issue as ipv4, looks not safe if you analyze header before doing
> sanity check.
OK.
>
>> +    if (RSC_WANT != virtio_net_rsc_sanity_check6(chain,
>> +                                                 unit.ip, buf, size)) {
>> +        return virtio_net_do_receive(nc, buf, size);
>> +    }
>> +
>> +    ret = virtio_net_rsc_tcp_ctrl_check(chain, unit.tcp);
>> +    if (ret == RSC_BYPASS) {
>> +        return virtio_net_do_receive(nc, buf, size);
>> +    } else if (ret == RSC_FINAL) {
>> +        return virtio_net_rsc_drain_flow(chain, nc, buf, size,
>> +                ((hdr_len + sizeof(struct eth_header)) + 8),
>> +                VIRTIO_NET_IP6_ADDR_SIZE,
>> +                hdr_len + sizeof(struct eth_header) + sizeof(struct
>> ip6_header),
>> +                VIRTIO_NET_TCP_PORT_SIZE);
>> +    }
>> +
>> +    if (virtio_net_rsc_empty_cache(chain, nc, buf, size)) {
>> +        return size;
>> +    }
>> +
>> +    return virtio_net_rsc_do_coalesce(chain, nc, buf, size, &unit);
>> +}
>> +
>>   static NetRscChain *virtio_net_rsc_lookup_chain(VirtIONet * n,
>>                                                   NetClientState *nc,
>>                                                   uint16_t proto)
>>   {
>>       NetRscChain *chain;
>> -    if (proto != (uint16_t)ETH_P_IP) {
>> +    if ((proto != (uint16_t)ETH_P_IP) && (proto !=
>> (uint16_t)ETH_P_IPV6)) {
>>           return NULL;
>>       }
>> @@ -2125,8 +2252,13 @@ static NetRscChain
>> *virtio_net_rsc_lookup_chain(VirtIONet * n,
>>       chain = g_malloc(sizeof(*chain));
>>       chain->n = n;
>>       chain->proto = proto;
>> -    chain->max_payload = VIRTIO_NET_MAX_IP4_PAYLOAD;
>> -    chain->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
>> +    if (proto == (uint16_t)ETH_P_IP) {
>> +        chain->max_payload = VIRTIO_NET_MAX_IP4_PAYLOAD;
>> +        chain->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
>> +    } else {
>> +        chain->max_payload = VIRTIO_NET_MAX_IP6_PAYLOAD;
>> +        chain->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
>> +    }
>>       chain->drain_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
>>                                         virtio_net_rsc_purge, chain);
>>       memset(&chain->stat, 0, sizeof(chain->stat));
>> @@ -2158,7 +2290,11 @@ static ssize_t
>> virtio_net_rsc_receive(NetClientState *nc,
>>           return virtio_net_do_receive(nc, buf, size);
>>       } else {
>>           chain->stat.received++;
>> -        return virtio_net_rsc_receive4(chain, nc, buf, size);
>> +        if (proto == (uint16_t)ETH_P_IP) {
>> +            return virtio_net_rsc_receive4(chain, nc, buf, size);
>> +        } else  {
>> +            return virtio_net_rsc_receive6(chain, nc, buf, size);
>> +        }
>>       }
>>   }
>
>