Looks good to me!
Acked-by: Mike Pattrick <m...@redhat.com>
On Sat, 2021-11-27 at 03:39 +0000, Peng He wrote:
> From: Peng He <xnhp0...@gmail.com>
>
> ipf_postprocess will emit packets into the datapath pipeline ignoring
> the conntrack context, this might casuse weird issues when a packet
> batch has less space to hold all the fragments belonging to single
> packet.
>
> Given the below ruleest and consider sending a 64K ICMP packet which
> is splitted into 64 fragments.
>
> priority=1,action=drop
> priority=10,arp,action=normal
> priority=100,in_port=1,ct_state=-trk,icmp,action=ct(zone=9,table=0)
> priority=100,in_port=1,ct_state=+new+trk,icmp,action=ct(zone=9,commit),2
> priority=100,in_port=1,ct_state=-new+est+trk,icmp,action=2
> priority=100,in_port=2,ct_state=-trk,icmp,action=ct(table=0,zone=9)
> priority=100,in_port=2,ct_state=+trk+est-new,icmp,action=1
>
> Batch 1:
> the first 32 packets will be buffered in the ipf preprocessing, nothing
> more proceeds.
>
> Batch 2:
> the second 32 packets succeed the fragment reassembly and goes to ct
> and ipf_post will emits the first 32 packets due to the limit of batch
> size.
>
> the first 32 packets goes to the datapath again due to the
> recirculation, and again buffered at ipf preprocessing before ct commit,
> then the ovs tries to call ct commit as well as ipf_postprocessing which emits
> the last 32 packets, in this case the last 32 packets will follow
> the current actions which will be sent to port 2 directly without
> recirculation and going to ipf preprocssing and ct commit again.
>
> This will cause the first 32 packets never get the chance to
> reassemble and evevntually this large ICMP packets fail to transmit.
>
> this patch fixes this issue by adding firstly ipf context to avoid
> ipf_postprocessing emits packets in the wrong context. Then by
> re-executing the action list again to emit the last 32 packets
> in the right context to correctly transmitting multiple fragments.
>
> This might be one of the root cause why the OVS log warns:
>
> "
> skipping output to input port on bridge br-int while processing
> "
>
> As a pkt might enter into different ipf context.
>
> Signed-off-by: Peng He <hepeng.0...@bytedance.com>
> Co-authored-by: Mike Pattrick <m...@redhat.com>
> ---
> lib/conntrack.c | 9 ++++---
> lib/conntrack.h | 15 ++++++------
> lib/dpif-netdev.c | 52 +++++++++++++++++++++++++++++++++++++----
> lib/ipf.c | 40 ++++++++++++++++++++++++-------
> lib/ipf.h | 11 +++++++--
> tests/system-traffic.at | 33 ++++++++++++++++++++++++++
> tests/test-conntrack.c | 6 ++---
> 7 files changed, 136 insertions(+), 30 deletions(-)
>
> diff --git a/lib/conntrack.c b/lib/conntrack.c
> index 33a1a9295..72999f1ae 100644
> --- a/lib/conntrack.c
> +++ b/lib/conntrack.c
> @@ -1434,14 +1434,14 @@ process_one(struct conntrack *ct, struct dp_packet
> *pkt,
> * connection tables. 'setmark', if not NULL, should point to a two
> * elements array containing a value and a mask to set the connection mark.
> * 'setlabel' behaves similarly for the connection label.*/
> -int
> +bool
> conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch,
> ovs_be16 dl_type, bool force, bool commit, uint16_t zone,
> const uint32_t *setmark,
> const struct ovs_key_ct_labels *setlabel,
> ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper,
> const struct nat_action_info_t *nat_action_info,
> - long long now, uint32_t tp_id)
> + long long now, uint32_t tp_id, struct ipf_ctx *ipf_ctx)
> {
> ipf_preprocess_conntrack(ct->ipf, pkt_batch, now, dl_type, zone,
> ct->hash_basis);
> @@ -1468,9 +1468,8 @@ conntrack_execute(struct conntrack *ct, struct
> dp_packet_batch *pkt_batch,
> }
> }
>
> - ipf_postprocess_conntrack(ct->ipf, pkt_batch, now, dl_type);
> -
> - return 0;
> + return ipf_postprocess_conntrack(ct->ipf, pkt_batch, ipf_ctx, \
> + now, dl_type);
> }
>
> void
> diff --git a/lib/conntrack.h b/lib/conntrack.h
> index 9553b188a..211efad3f 100644
> --- a/lib/conntrack.h
> +++ b/lib/conntrack.h
> @@ -64,6 +64,7 @@
> struct dp_packet_batch;
>
> struct conntrack;
> +struct ipf_ctx;
>
> union ct_addr {
> ovs_be32 ipv4;
> @@ -88,13 +89,13 @@ struct nat_action_info_t {
> struct conntrack *conntrack_init(void);
> void conntrack_destroy(struct conntrack *);
>
> -int conntrack_execute(struct conntrack *ct, struct dp_packet_batch
> *pkt_batch,
> - ovs_be16 dl_type, bool force, bool commit, uint16_t
> zone,
> - const uint32_t *setmark,
> - const struct ovs_key_ct_labels *setlabel,
> - ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper,
> - const struct nat_action_info_t *nat_action_info,
> - long long now, uint32_t tp_id);
> +bool conntrack_execute(struct conntrack *ct, struct dp_packet_batch
> *pkt_batch,
> + ovs_be16 dl_type, bool force, bool commit,
> + uint16_t zone, const uint32_t *setmark,
> + const struct ovs_key_ct_labels *setlabel,
> + ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper,
> + const struct nat_action_info_t *nat_action_info,
> + long long now, uint32_t tp_id, struct ipf_ctx
> *ipf_ctx);
> void conntrack_clear(struct dp_packet *packet);
>
> struct conntrack_dump {
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 98453a206..af928a6fa 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -7756,6 +7756,7 @@ dp_netdev_recirculate(struct dp_netdev_pmd_thread *pmd,
> struct dp_netdev_execute_aux {
> struct dp_netdev_pmd_thread *pmd;
> const struct flow *flow;
> + const struct nlattr *redo_actions;
> };
>
> static void
> @@ -8285,10 +8286,23 @@ dp_execute_cb(void *aux_, struct dp_packet_batch
> *packets_,
> VLOG_WARN_RL(&rl, "NAT specified without commit.");
> }
>
> - conntrack_execute(dp->conntrack, packets_, aux->flow->dl_type, force,
> - commit, zone, setmark, setlabel, aux->flow->tp_src,
> - aux->flow->tp_dst, helper, nat_action_info_ref,
> - pmd->ctx.now / 1000, tp_id);
> + bool more_pkts;
> + struct ipf_ctx ipf_ctx = { aux->flow->recirc_id,
> + aux->flow->in_port,
> + zone };
> + more_pkts = conntrack_execute(dp->conntrack, packets_,
> + aux->flow->dl_type,
> + force, commit, zone,
> + setmark, setlabel,
> + aux->flow->tp_src,
> + aux->flow->tp_dst,
> + helper, nat_action_info_ref,
> + pmd->ctx.now / 1000, tp_id, &ipf_ctx);
> + if (more_pkts) {
> + aux->redo_actions = a;
> + } else {
> + aux->redo_actions = NULL;
> + }
> break;
> }
>
> @@ -8322,16 +8336,44 @@ dp_execute_cb(void *aux_, struct dp_packet_batch
> *packets_,
> dp_packet_delete_batch(packets_, should_steal);
> }
>
> +static size_t
> +dp_netdev_find_actions_left(const struct nlattr *actions,
> + size_t actions_len,
> + const struct nlattr *target)
> +{
> + const struct nlattr *a;
> + size_t left;
> + NL_ATTR_FOR_EACH_UNSAFE (a, left, actions, actions_len) {
> + if (a == target) {
> + break;
> + }
> + }
> + return left;
> +}
> +
> static void
> dp_netdev_execute_actions(struct dp_netdev_pmd_thread *pmd,
> struct dp_packet_batch *packets,
> bool should_steal, const struct flow *flow,
> const struct nlattr *actions, size_t actions_len)
> {
> - struct dp_netdev_execute_aux aux = { pmd, flow };
> + int max_reexec = 2;
> + struct dp_netdev_execute_aux aux = { pmd, flow, NULL };
>
> odp_execute_actions(&aux, packets, should_steal, actions,
> actions_len, dp_execute_cb);
> +
> + while (OVS_UNLIKELY(aux.redo_actions && max_reexec --)) {
> + struct dp_packet_batch batch;
> + dp_packet_batch_init(&batch);
> + size_t redo_actions_len = \
> + dp_netdev_find_actions_left(actions,
> + actions_len,
> + aux.redo_actions);
> +
> + odp_execute_actions(&aux, &batch, should_steal,
> + aux.redo_actions, redo_actions_len, dp_execute_cb);
> + }
> }
>
> struct dp_netdev_ct_dump {
> diff --git a/lib/ipf.c b/lib/ipf.c
> index 507db2aea..1fd3d8d30 100644
> --- a/lib/ipf.c
> +++ b/lib/ipf.c
> @@ -1046,30 +1046,52 @@ ipf_send_frags_in_list(struct ipf *ipf, struct
> ipf_list *ipf_list,
> OVS_NOT_REACHED();
> }
>
> +static bool
> +ipf_ctx_eq(struct ipf_list *ipf_list, struct ipf_ctx *ctx)
> +{
> + struct dp_packet *pkt =
> + ipf_list->frag_list[ipf_list->last_sent_idx + 1].pkt;
> +
> + if (pkt->md.recirc_id != ctx->recirc_id ||
> + pkt->md.in_port.odp_port != ctx->in_port.odp_port ||
> + pkt->md.ct_zone != ctx->zone) {
> + return false;
> + }
> + return true;
> +}
> +
> /* Adds fragments associated with a completed fragment list to a packet batch
> * to be processed by the calling application, typically conntrack. Also
> * cleans up the list context when it is empty.*/
> -static void
> +static bool
> ipf_send_completed_frags(struct ipf *ipf, struct dp_packet_batch *pb,
> - long long now, bool v6)
> + struct ipf_ctx *ctx, long long now, bool v6)
> {
> if (ovs_list_is_empty(&ipf->frag_complete_list)) {
> - return;
> + return false;
> }
>
> + bool more_pkts = false;
> ovs_mutex_lock(&ipf->ipf_lock);
> struct ipf_list *ipf_list, *next;
>
> LIST_FOR_EACH_SAFE (ipf_list, next, list_node, &ipf->frag_complete_list)
> {
> +
> + if (ctx && !ipf_ctx_eq(ipf_list, ctx)) {
> + continue;
> + }
> +
> if (ipf_send_frags_in_list(ipf, ipf_list, pb,
> IPF_FRAG_COMPLETED_LIST,
> v6, now)) {
> ipf_completed_list_clean(&ipf->frag_lists, ipf_list);
> } else {
> + more_pkts = true;
> break;
> }
> }
>
> ovs_mutex_unlock(&ipf->ipf_lock);
> + return more_pkts;
> }
>
> /* Conservatively adds fragments associated with a expired fragment list to
> @@ -1225,8 +1247,8 @@ ipf_post_execute_reass_pkts(struct ipf *ipf,
> * be added to the batch to be sent through conntrack. */
> void
> ipf_preprocess_conntrack(struct ipf *ipf, struct dp_packet_batch *pb,
> - long long now, ovs_be16 dl_type, uint16_t zone,
> - uint32_t hash_basis)
> + long long now, ovs_be16 dl_type,
> + uint16_t zone, uint32_t hash_basis)
> {
> if (ipf_get_enabled(ipf)) {
> ipf_extract_frags_from_batch(ipf, pb, dl_type, zone, now,
> hash_basis);
> @@ -1241,16 +1263,18 @@ ipf_preprocess_conntrack(struct ipf *ipf, struct
> dp_packet_batch *pb,
> * through conntrack and adds these fragments to any batches seen. Expired
> * fragments are marked as invalid and also added to the batches seen
> * with low priority. Reassembled packets are freed. */
> -void
> +bool
> ipf_postprocess_conntrack(struct ipf *ipf, struct dp_packet_batch *pb,
> - long long now, ovs_be16 dl_type)
> + struct ipf_ctx *ctx, long long now, ovs_be16
> dl_type)
> {
> + bool more_pkts = false;
> if (ipf_get_enabled(ipf) || atomic_count_get(&ipf->nfrag)) {
> bool v6 = dl_type == htons(ETH_TYPE_IPV6);
> ipf_post_execute_reass_pkts(ipf, pb, v6);
> - ipf_send_completed_frags(ipf, pb, now, v6);
> + more_pkts = ipf_send_completed_frags(ipf, pb, ctx, now, v6);
> ipf_send_expired_frags(ipf, pb, now, v6);
> }
> + return more_pkts;
> }
>
> static void *
> diff --git a/lib/ipf.h b/lib/ipf.h
> index 6ac91b270..7bbf453af 100644
> --- a/lib/ipf.h
> +++ b/lib/ipf.h
> @@ -40,14 +40,21 @@ struct ipf_status {
> unsigned int nfrag_max;
> };
>
> +struct ipf_ctx {
> + uint32_t recirc_id;
> + union flow_in_port in_port; /* Input port. */
> + uint16_t zone;
> +};
> +
> struct ipf *ipf_init(void);
> void ipf_destroy(struct ipf *ipf);
> void ipf_preprocess_conntrack(struct ipf *ipf, struct dp_packet_batch *pb,
> long long now, ovs_be16 dl_type, uint16_t zone,
> uint32_t hash_basis);
>
> -void ipf_postprocess_conntrack(struct ipf *ipf, struct dp_packet_batch *pb,
> - long long now, ovs_be16 dl_type);
> +bool ipf_postprocess_conntrack(struct ipf *ipf, struct dp_packet_batch *pb,
> + struct ipf_ctx *ctx, long long now,
> + ovs_be16 dl_type);
>
> int ipf_set_enabled(struct ipf *ipf, bool v6, bool enable);
> int ipf_set_min_frag(struct ipf *ipf, bool v6, uint32_t value);
> diff --git a/tests/system-traffic.at b/tests/system-traffic.at
> index a69896d33..a09318882 100644
> --- a/tests/system-traffic.at
> +++ b/tests/system-traffic.at
> @@ -2741,6 +2741,39 @@ DPCTL_CHECK_FRAGMENTATION_PASS()
> OVS_TRAFFIC_VSWITCHD_STOP
> AT_CLEANUP
>
> +AT_SETUP([conntrack - IPv4 large fragmentation])
> +CHECK_CONNTRACK()
> +OVS_TRAFFIC_VSWITCHD_START()
> +
> +ADD_NAMESPACES(at_ns0, at_ns1)
> +
> +ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24")
> +ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24")
> +
> +dnl Sending ping through conntrack
> +AT_DATA([flows.txt], [dnl
> +priority=1,action=drop
> +priority=10,arp,action=normal
> +priority=100,in_port=1,ct_state=-trk,icmp,action=ct(zone=9,table=0)
> +priority=100,in_port=1,ct_state=+new+trk,icmp,action=ct(zone=9,commit),2
> +priority=100,in_port=1,ct_state=-new+est+trk,icmp,action=2
> +priority=100,in_port=2,ct_state=-trk,icmp,action=ct(table=0,zone=9)
> +priority=100,in_port=2,ct_state=+trk+est-new,icmp,action=1
> +])
> +
> +AT_CHECK([ovs-ofctl --bundle add-flows br0 flows.txt])
> +
> +dnl Modify userspace conntrack fragmentation handling.
> +DPCTL_MODIFY_FRAGMENTATION()
> +
> +dnl Ipv4 larger fragmentation connectivity check.
> +NS_CHECK_EXEC([at_ns0], [ping -s 65000 -q -c 3 -i 0.3 -w 2 10.1.1.2 |
> FORMAT_PING], [0], [dnl
> +3 packets transmitted, 3 received, 0% packet loss, time 0ms
> +])
> +
> +OVS_TRAFFIC_VSWITCHD_STOP
> +AT_CLEANUP
> +
> AT_SETUP([conntrack - IPv4 fragmentation expiry])
> CHECK_CONNTRACK()
> OVS_TRAFFIC_VSWITCHD_START()
> diff --git a/tests/test-conntrack.c b/tests/test-conntrack.c
> index 24c93e4a4..f90b7aa78 100644
> --- a/tests/test-conntrack.c
> +++ b/tests/test-conntrack.c
> @@ -91,7 +91,7 @@ ct_thread_main(void *aux_)
> ovs_barrier_block(&barrier);
> for (i = 0; i < n_pkts; i += batch_size) {
> conntrack_execute(ct, pkt_batch, dl_type, false, true, 0, NULL, NULL,
> - 0, 0, NULL, NULL, now, 0);
> + 0, 0, NULL, NULL, now, 0, NULL);
> DP_PACKET_BATCH_FOR_EACH (j, pkt, pkt_batch) {
> pkt_metadata_init_conn(&pkt->md);
> }
> @@ -178,7 +178,7 @@ pcap_batch_execute_conntrack(struct conntrack *ct_,
>
> if (flow.dl_type != dl_type) {
> conntrack_execute(ct_, &new_batch, dl_type, false, true, 0,
> - NULL, NULL, 0, 0, NULL, NULL, now, 0);
> + NULL, NULL, 0, 0, NULL, NULL, now, 0, NULL);
> dp_packet_batch_init(&new_batch);
> }
> dp_packet_batch_add(&new_batch, packet);
> @@ -186,7 +186,7 @@ pcap_batch_execute_conntrack(struct conntrack *ct_,
>
> if (!dp_packet_batch_is_empty(&new_batch)) {
> conntrack_execute(ct_, &new_batch, dl_type, false, true, 0, NULL,
> NULL,
> - 0, 0, NULL, NULL, now, 0);
> + 0, 0, NULL, NULL, now, 0, NULL);
> }
>
> }
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