[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC PATCH V3 4/4] colo-compare: add TCP, UDP, ICMP pac
From: |
Jason Wang |
Subject: |
Re: [Qemu-devel] [RFC PATCH V3 4/4] colo-compare: add TCP, UDP, ICMP packet comparison |
Date: |
Thu, 28 Apr 2016 16:15:45 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 04/18/2016 07:11 PM, Zhang Chen wrote:
> Signed-off-by: Zhang Chen <address@hidden>
> Signed-off-by: Li Zhijian <address@hidden>
> Signed-off-by: Wen Congyang <address@hidden>
> ---
> net/colo-compare.c | 158
> +++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 154 insertions(+), 4 deletions(-)
I'm not a tcp expert, this patch may need some guys who are good at TCP
to review.
> diff --git a/net/colo-compare.c b/net/colo-compare.c
> index 4b5a2d4..3dad461 100644
> --- a/net/colo-compare.c
> +++ b/net/colo-compare.c
> @@ -385,9 +385,148 @@ static int colo_packet_compare(Packet *ppkt, Packet
> *spkt)
> }
> }
>
> -static int colo_packet_compare_all(Packet *spkt, Packet *ppkt)
> +/*
> + * called from the compare thread on the primary
> + * for compare tcp packet
> + * compare_tcp copied from Dr. David Alan Gilbert's branch
> + */
> +static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
> +{
> + struct tcphdr *ptcp, *stcp;
> + int res;
> + char *sdebug, *ddebug;
> + ptrdiff_t offset;
> +
> + trace_colo_compare_main("compare tcp");
> + ptcp = (struct tcphdr *)ppkt->transport_layer;
> + stcp = (struct tcphdr *)spkt->transport_layer;
> +
> + /* Initial is compare the whole packet */
> + offset = 12; /* Hack! Skip virtio header */
So this won't work for e1000 I believe?
> +
> + if (ptcp->th_flags == stcp->th_flags &&
> + ((ptcp->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
> + /* This is the syn/ack response from the guest to an incoming
> + * connection; the secondary won't have matched the sequence number
> + * Note: We should probably compare the IP level?
> + * Note hack: This already has the virtio offset
> + */
> + offset = sizeof(ptcp->th_ack) + (void *)&ptcp->th_ack - ppkt->data;
> + }
> + /* Note - we want to compare everything as long as it's not the syn/ack?
> */
> + assert(offset > 0);
> + assert(spkt->size > offset);
> +
> + /* The 'identification' field in the IP header is *very* random
> + * it almost never matches. Fudge this by ignoring differences in
> + * unfragmented packets; they'll normally sort themselves out if
> different
> + * anyway, and it should recover at the TCP level.
> + * An alternative would be to get both the primary and secondary to
> rewrite
> + * somehow; but that would need some sync traffic to sync the state
This is very tricky I believe, I wonder this will work. Would it be
easier if we reassembly the packet?
And I believe we should check for the length before all the other
examinations?
> + */
> + if (ntohs(ppkt->ip->ip_off) & IP_DF) {
> + spkt->ip->ip_id = ppkt->ip->ip_id;
> + /* and the sum will be different if the IDs were different */
> + spkt->ip->ip_sum = ppkt->ip->ip_sum;
> + }
> +
> + res = memcmp(ppkt->data + offset, spkt->data + offset,
> + (spkt->size - offset));
> +
> + if (res && DEBUG_TCP_COMPARE) {
> + sdebug = strdup(inet_ntoa(ppkt->ip->ip_src));
> + ddebug = strdup(inet_ntoa(ppkt->ip->ip_dst));
> + fprintf(stderr, "%s: src/dst: %s/%s offset=%zd p: seq/ack=%u/%u"
> + " s: seq/ack=%u/%u res=%d flags=%x/%x\n", __func__,
> + sdebug, ddebug, offset,
> + ntohl(ptcp->th_seq), ntohl(ptcp->th_ack),
> + ntohl(stcp->th_seq), ntohl(stcp->th_ack),
> + res, ptcp->th_flags, stcp->th_flags);
> + if (res && (ptcp->th_seq == stcp->th_seq)) {
> + trace_colo_compare_with_int("Primary len", ppkt->size);
> + colo_dump_packet(ppkt);
> + trace_colo_compare_with_int("Secondary len", spkt->size);
> + colo_dump_packet(spkt);
> + }
> + g_free(sdebug);
> + g_free(ddebug);
> + }
> +
> + return res;
> +}
> +
> +/*
> + * called from the compare thread on the primary
> + * for compare udp packet
> + */
> +static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
> +{
> + int ret = 1;
> +
> + trace_colo_compare_main("compare udp");
> + ret = colo_packet_compare(ppkt, spkt);
> +
> + if (ret) {
> + trace_colo_compare_main("primary udp");
> + colo_dump_packet(ppkt);
> + trace_colo_compare_main("secondary udp");
> + colo_dump_packet(spkt);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * called from the compare thread on the primary
> + * for compare icmp packet
> + */
> +static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
> +{
> + int network_length;
> + struct icmp *icmp_ppkt, *icmp_spkt;
> +
> + trace_colo_compare_main("compare icmp");
> + network_length = (ppkt->ip->ip_hl & 0x0F) * 4;
> + icmp_ppkt = (struct icmp *)(ppkt->data + network_length + ETH_HLEN);
> + icmp_spkt = (struct icmp *)(spkt->data + network_length + ETH_HLEN);
> +
> + if ((icmp_ppkt->icmp_type == icmp_spkt->icmp_type) &&
> + (icmp_ppkt->icmp_code == icmp_spkt->icmp_code)) {
> + if (icmp_ppkt->icmp_type == ICMP_REDIRECT) {
> + if (icmp_ppkt->icmp_gwaddr.s_addr !=
> + icmp_spkt->icmp_gwaddr.s_addr) {
> + trace_colo_compare_main("icmp_gwaddr.s_addr not same");
> + trace_colo_compare_with_char("ppkt s_addr",
> + inet_ntoa(icmp_ppkt->icmp_gwaddr));
> + trace_colo_compare_with_char("spkt s_addr",
> + inet_ntoa(icmp_spkt->icmp_gwaddr));
> + return -1;
> + }
> + } else if ((icmp_ppkt->icmp_type == ICMP_UNREACH) &&
> + (icmp_ppkt->icmp_type == ICMP_UNREACH_NEEDFRAG)) {
> + if (icmp_ppkt->icmp_nextmtu != icmp_spkt->icmp_nextmtu) {
> + trace_colo_compare_main("icmp_nextmtu not same");
> + trace_colo_compare_with_int("ppkt s_addr",
> + icmp_ppkt->icmp_nextmtu);
> + trace_colo_compare_with_int("spkt s_addr",
> + icmp_spkt->icmp_nextmtu);
> + return -1;
> + }
> + }
> + } else {
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * called from the compare thread on the primary
> + * for compare other packet
> + */
> +static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
> {
> - trace_colo_compare_main("compare all");
> + trace_colo_compare_main("compare other");
> return colo_packet_compare(ppkt, spkt);
> }
>
> @@ -406,8 +545,19 @@ static void colo_compare_connection(void *opaque, void
> *user_data)
> while (!g_queue_is_empty(&conn->primary_list) &&
> !g_queue_is_empty(&conn->secondary_list)) {
> pkt = g_queue_pop_head(&conn->primary_list);
> - result = g_queue_find_custom(&conn->secondary_list,
> - pkt, (GCompareFunc)colo_packet_compare_all);
> + if (conn->ip_proto == IPPROTO_TCP) {
> + result = g_queue_find_custom(&conn->secondary_list,
> + pkt, (GCompareFunc)colo_packet_compare_tcp);
> + } else if (conn->ip_proto == IPPROTO_UDP) {
> + result = g_queue_find_custom(&conn->secondary_list,
> + pkt, (GCompareFunc)colo_packet_compare_udp);
> + } else if (conn->ip_proto == IPPROTO_ICMP) {
> + result = g_queue_find_custom(&conn->secondary_list,
> + pkt, (GCompareFunc)colo_packet_compare_icmp);
> + } else {
> + result = g_queue_find_custom(&conn->secondary_list,
> + pkt, (GCompareFunc)colo_packet_compare_other);
> + }
>
A switch...case looks better.
> if (result) {
> ret = compare_chr_send(pkt->s->chr_out, pkt->data, pkt->size);
- [Qemu-devel] [RFC PATCH V3 0/4] Introduce COLO-compare, Zhang Chen, 2016/04/18
- [Qemu-devel] [RFC PATCH V3 4/4] colo-compare: add TCP, UDP, ICMP packet comparison, Zhang Chen, 2016/04/18
- [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Zhang Chen, 2016/04/18
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Jason Wang, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Jason Wang, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Zhang Chen, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Jason Wang, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Zhang Chen, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Jason Wang, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Zhang Chen, 2016/04/28
- Re: [Qemu-devel] [RFC PATCH V3 1/4] colo-compare: introduce colo compare initlization, Zhang Chen, 2016/04/28