[ovs-dev] [PATCH v17 5/8] dpif-offload-netlink: Implement dpif-offload-provider API

Eelco Chaudron echaudro at redhat.com
Fri Nov 5 13:24:22 UTC 2021


On 21 Oct 2021, at 10:01, Chris Mi wrote:

> Implement dpif-offload API for netlink datapath.
>
> Signed-off-by: Chris Mi <cmi at nvidia.com>
> Reviewed-by: Eli Britstein <elibr at nvidia.com>
> Acked-by: Eelco Chaudron <echaudro at redhat.com>

Chris, if you make changes to this patch after I have ACKed it, you need to remove the acked-by.
See some comments inline below.

> ---
>  lib/automake.mk             |   1 +
>  lib/dpif-netdev.c           |   3 +-
>  lib/dpif-netlink.c          |  11 +-
>  lib/dpif-offload-netlink.c  | 207 ++++++++++++++++++++++++++++++++++++
>  lib/dpif-offload-provider.h |  15 ++-
>  lib/dpif-provider.h         |   3 +-
>  lib/dpif.c                  |   3 +-
>  7 files changed, 237 insertions(+), 6 deletions(-)
>  create mode 100644 lib/dpif-offload-netlink.c
>
> diff --git a/lib/automake.mk b/lib/automake.mk
> index 9259f57de..18cffa827 100644
> --- a/lib/automake.mk
> +++ b/lib/automake.mk
> @@ -446,6 +446,7 @@ lib_libopenvswitch_la_SOURCES += \
>  	lib/dpif-netlink.h \
>  	lib/dpif-netlink-rtnl.c \
>  	lib/dpif-netlink-rtnl.h \
> +	lib/dpif-offload-netlink.c \
>  	lib/if-notifier.c \
>  	lib/netdev-linux.c \
>  	lib/netdev-linux.h \
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index b078c2da5..3f6d2ead7 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -1593,7 +1593,8 @@ create_dpif_netdev(struct dp_netdev *dp)
>      ovs_refcount_ref(&dp->ref_cnt);
>
>      dpif = xmalloc(sizeof *dpif);
> -    dpif_init(&dpif->dpif, dp->class, dp->name, netflow_id >> 8, netflow_id);
> +    dpif_init(&dpif->dpif, dp->class, NULL, dp->name, netflow_id >> 8,
> +              netflow_id);
>      dpif->dp = dp;
>      dpif->last_port_seq = seq_read(dp->port_seq);
>
> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
> index 5f4b60c5a..4dea2f76c 100644
> --- a/lib/dpif-netlink.c
> +++ b/lib/dpif-netlink.c
> @@ -370,6 +370,12 @@ dpif_netlink_open(const struct dpif_class *class OVS_UNUSED, const char *name,
>
>      if (create) {
>          dp_request.cmd = OVS_DP_CMD_NEW;
> +        error = dpif_offload_netlink_init();

I think the init should still be a callback into the dpif_offload_class, and when it gets registered the init function should be called.
Not sure if it’s the correct place, but you could do something similar in dp_initialize() as done with  dp_register_provider().

> +        if (error) {
> +            VLOG_WARN("Failed to initialize netlink offload datapath: %s",
> +                      ovs_strerror(error));

VLOG_ERR()?

> +            return error;
> +        }
>      } else {
>          dp_request.cmd = OVS_DP_CMD_GET;
>
> @@ -460,8 +466,8 @@ open_dpif(const struct dpif_netlink_dp *dp, struct dpif **dpifp)
>      dpif->port_notifier = NULL;
>      fat_rwlock_init(&dpif->upcall_lock);
>
> -    dpif_init(&dpif->dpif, &dpif_netlink_class, dp->name,
> -              dp->dp_ifindex, dp->dp_ifindex);
> +    dpif_init(&dpif->dpif, &dpif_netlink_class, &dpif_offload_netlink,

Guess naming should me more offload class related, so maybe rename it to “dpif_offload_netlink_class”.

> +              dp->name, dp->dp_ifindex, dp->dp_ifindex);
>
>      dpif->dp_ifindex = dp->dp_ifindex;
>      dpif->user_features = dp->user_features;
> @@ -732,6 +738,7 @@ dpif_netlink_destroy(struct dpif *dpif_)
>      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
>      struct dpif_netlink_dp dp;
>
> +    dpif_offload_netlink_destroy();
>      dpif_netlink_dp_init(&dp);
>      dp.cmd = OVS_DP_CMD_DEL;
>      dp.dp_ifindex = dpif->dp_ifindex;
> diff --git a/lib/dpif-offload-netlink.c b/lib/dpif-offload-netlink.c
> new file mode 100644
> index 000000000..7f53ed582
> --- /dev/null
> +++ b/lib/dpif-offload-netlink.c
> @@ -0,0 +1,207 @@
> +/*
> + * Copyright (c) 2021, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
> + *
> + * Licensed under the Apache License, Version 2.0 (the "License");
> + * you may not use this file except in compliance with the License.
> + * You may obtain a copy of the License at:
> + *
> + *     http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +
> +#include <config.h>
> +#include <errno.h>
> +#include <linux/psample.h>
> +#include <sys/poll.h>
> +
> +#include "dpif-offload-provider.h"
> +#include "netdev-offload.h"
> +#include "netlink-protocol.h"
> +#include "netlink-socket.h"
> +#include "openvswitch/vlog.h"
> +
> +VLOG_DEFINE_THIS_MODULE(dpif_offload_netlink);
> +
> +static struct nl_sock *psample_sock;
> +static int psample_family;
> +
> +/* Receive psample netlink message and save the attributes. */
> +struct offload_psample {
> +    struct nlattr *packet;      /* Packet data. */
> +    int dp_group_id;            /* Mapping id for sFlow offload. */
> +    int iifindex;               /* Input ifindex. */
> +};
> +
> +/* In order to keep compatibility with kernels without psample module,
> + * return success even if psample is not initialized successfully. */
> +int
> +dpif_offload_netlink_init(void)
> +{
> +    unsigned int psample_mcgroup;
> +    int err;
> +
> +    if (!netdev_is_flow_api_enabled()) {
> +        VLOG_DBG("Flow API is not enabled.");
> +        return 0;
> +    }
> +
> +    if (psample_sock) {
> +        VLOG_DBG("Psample socket is already initialized.");
> +        return 0;
> +    }
> +
> +    err = nl_lookup_genl_family(PSAMPLE_GENL_NAME,
> +                                &psample_family);
> +    if (err) {
> +        VLOG_WARN("Generic Netlink family '%s' does not exist: %s\n"
> +                  "Please make sure the kernel module psample is loaded.",
> +                  PSAMPLE_GENL_NAME, ovs_strerror(err));
> +        return 0;
> +    }
> +
> +    err = nl_lookup_genl_mcgroup(PSAMPLE_GENL_NAME,
> +                                 PSAMPLE_NL_MCGRP_SAMPLE_NAME,
> +                                 &psample_mcgroup);
> +    if (err) {
> +        VLOG_WARN("Failed to join Netlink multicast group '%s': %s",
> +                  PSAMPLE_NL_MCGRP_SAMPLE_NAME, ovs_strerror(err));
> +        return 0;
> +    }
> +
> +    err = nl_sock_create(NETLINK_GENERIC, &psample_sock);
> +    if (err) {
> +        VLOG_WARN("Failed to create psample socket: %s", ovs_strerror(err));
> +        return 0;
> +    }
> +
> +    err = nl_sock_join_mcgroup(psample_sock, psample_mcgroup);
> +    if (err) {
> +        VLOG_WARN("Failed to join psample mcgroup: %s", ovs_strerror(err));
> +        nl_sock_destroy(psample_sock);
> +        psample_sock = NULL;
> +        return 0;
> +    }
> +
> +    return 0;
> +}
> +
> +void
> +dpif_offload_netlink_destroy(void)
> +{
> +    if (!psample_sock) {
> +        return;
> +    }
> +
> +    nl_sock_destroy(psample_sock);
> +    psample_sock = NULL;
> +}
> +
> +static void
> +dpif_offload_netlink_sflow_recv_wait(void)
> +{
> +    if (psample_sock) {
> +        nl_sock_wait(psample_sock, POLLIN);
> +    }
> +}
> +
> +static int
> +psample_from_ofpbuf(struct offload_psample *psample,
> +                    const struct ofpbuf *buf)
> +{
> +    static const struct nl_policy ovs_psample_policy[] = {
> +        [PSAMPLE_ATTR_IIFINDEX] = { .type = NL_A_U16 },
> +        [PSAMPLE_ATTR_SAMPLE_GROUP] = { .type = NL_A_U32 },
> +        [PSAMPLE_ATTR_GROUP_SEQ] = { .type = NL_A_U32 },
> +        [PSAMPLE_ATTR_DATA] = { .type = NL_A_UNSPEC },
> +    };
> +    struct nlattr *a[ARRAY_SIZE(ovs_psample_policy)];
> +    struct genlmsghdr *genl;
> +    struct nlmsghdr *nlmsg;
> +    struct ofpbuf b;
> +
> +    b = ofpbuf_const_initializer(buf->data, buf->size);
> +    nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
> +    genl = ofpbuf_try_pull(&b, sizeof *genl);
> +    if (!nlmsg || !genl || nlmsg->nlmsg_type != psample_family
> +        || !nl_policy_parse(&b, 0, ovs_psample_policy, a,
> +                            ARRAY_SIZE(ovs_psample_policy))) {
> +        return EINVAL;
> +    }
> +
> +    psample->iifindex = nl_attr_get_u16(a[PSAMPLE_ATTR_IIFINDEX]);
> +    psample->dp_group_id = nl_attr_get_u32(a[PSAMPLE_ATTR_SAMPLE_GROUP]);
> +    psample->packet = a[PSAMPLE_ATTR_DATA];
> +
> +    return 0;
> +}
> +
> +static int
> +psample_parse_packet(struct offload_psample *psample,
> +                     struct dpif_offload_sflow *sflow)
> +{
> +    dp_packet_use_stub(&sflow->packet,
> +                       CONST_CAST(struct nlattr *,
> +                                  nl_attr_get(psample->packet)) - 1,
> +                       nl_attr_get_size(psample->packet) +
> +                       sizeof(struct nlattr));
> +    dp_packet_set_data(&sflow->packet,
> +                       (char *) dp_packet_data(&sflow->packet) +
> +                       sizeof(struct nlattr));
> +    dp_packet_set_size(&sflow->packet, nl_attr_get_size(psample->packet));
> +
> +    sflow->attr = dpif_offload_sflow_attr_find(psample->dp_group_id);
> +    if (!sflow->attr) {
> +        return ENOENT;
> +    }
> +    sflow->iifindex = psample->iifindex;
> +
> +    return 0;
> +}
> +
> +static int
> +dpif_offload_netlink_sflow_recv(struct dpif_offload_sflow *sflow)
> +{
> +    if (!psample_sock) {
> +        return ENOENT;
> +    }
> +
> +    for (;;) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        struct offload_psample psample;
> +        uint64_t buf_stub[4096 / 8];
> +        struct ofpbuf buf;
> +        int error;
> +
> +        ofpbuf_use_stub(&buf, buf_stub, sizeof buf_stub);
> +        error = nl_sock_recv(psample_sock, &buf, NULL, false);
> +
> +        if (!error) {
> +            error = psample_from_ofpbuf(&psample, &buf);
> +            if (!error) {
> +                    ofpbuf_uninit(&buf);
> +                    error = psample_parse_packet(&psample, sflow);
> +                    return error;
> +            }
> +        } else if (error != EAGAIN) {
> +            VLOG_WARN_RL(&rl, "Error reading or parsing netlink (%s).",
> +                         ovs_strerror(error));
> +            nl_sock_drain(psample_sock);
> +            error = ENOBUFS;
> +        }
> +
> +        ofpbuf_uninit(&buf);
> +        if (error) {
> +            return error;
> +        }
> +    }
> +}
> +
> +const struct dpif_offload_api dpif_offload_netlink = {

Think the structure definition for dpif_offload_api should change to dpif_offload_class.
And this structure to dpif_offload_netlink_class, see also previous comment.

> +    .sflow_recv_wait = dpif_offload_netlink_sflow_recv_wait,
> +    .sflow_recv = dpif_offload_netlink_sflow_recv,
> +};
> diff --git a/lib/dpif-offload-provider.h b/lib/dpif-offload-provider.h
> index 5b4726ab6..5ac419516 100644
> --- a/lib/dpif-offload-provider.h
> +++ b/lib/dpif-offload-provider.h
> @@ -17,12 +17,12 @@
>  #ifndef DPIF_OFFLOAD_PROVIDER_H
>  #define DPIF_OFFLOAD_PROVIDER_H
>
> +#include "dp-packet.h"
>  #include "netlink-protocol.h"
>  #include "openvswitch/packets.h"
>  #include "openvswitch/types.h"
>
>  struct dpif;
> -struct dpif_offload_sflow;
>
>  /* When offloading sample action, userspace creates a unique ID to map
>   * sFlow action and tunnel info and passes this ID to datapath instead
> @@ -37,6 +37,13 @@ struct dpif_sflow_attr {
>      ovs_u128 ufid;                  /* Flow ufid. */
>  };
>
> +/* Parse the specific dpif message to sFlow. So OVS can process it. */
> +struct dpif_offload_sflow {
> +    struct dp_packet packet;            /* Packet data. */
> +    uint32_t iifindex;                  /* Input ifindex. */
> +    const struct dpif_sflow_attr *attr; /* SFlow attribute. */
> +};
> +
>  /* Datapath interface offload structure, to be defined by each implementation
>   * of a datapath interface.
>   */
> @@ -54,4 +61,10 @@ void dpif_offload_sflow_recv_wait(const struct dpif *dpif);
>  int dpif_offload_sflow_recv(const struct dpif *dpif,
>                              struct dpif_offload_sflow *sflow);
>
> +#ifdef __linux__
> +extern const struct dpif_offload_api dpif_offload_netlink;
> +int dpif_offload_netlink_init(void);
> +void dpif_offload_netlink_destroy(void);
> +#endif
> +
>  #endif /* DPIF_OFFLOAD_PROVIDER_H */
> diff --git a/lib/dpif-provider.h b/lib/dpif-provider.h
> index 15a0d2b63..86898d838 100644
> --- a/lib/dpif-provider.h
> +++ b/lib/dpif-provider.h
> @@ -47,7 +47,8 @@ struct dpif {
>  struct dpif_ipf_status;
>  struct ipf_dump_ctx;
>
> -void dpif_init(struct dpif *, const struct dpif_class *, const char *name,
> +void dpif_init(struct dpif *, const struct dpif_class *,
> +               const struct dpif_offload_api *offload_api, const char *name,
>                 uint8_t netflow_engine_type, uint8_t netflow_engine_id);
>  void dpif_uninit(struct dpif *dpif, bool close);
>
> diff --git a/lib/dpif.c b/lib/dpif.c
> index 8c4aed47b..09ffa18e3 100644
> --- a/lib/dpif.c
> +++ b/lib/dpif.c
> @@ -1680,10 +1680,11 @@ dpif_queue_to_priority(const struct dpif *dpif, uint32_t queue_id,
>  

>  void
>  dpif_init(struct dpif *dpif, const struct dpif_class *dpif_class,
> -          const char *name,
> +          const struct dpif_offload_api *offload_api, const char *name,
Change dpif_offload_api to dpif_offload_api *offload_class
>            uint8_t netflow_engine_type, uint8_t netflow_engine_id)
>  {
>      dpif->dpif_class = dpif_class;
> +    dpif->offload_api = offload_api;

I would change the entry in the dpif structure from offload_api top offload_class.

>      dpif->base_name = xstrdup(name);
>      dpif->full_name = xasprintf("%s@%s", dpif_class->type, name);
>      dpif->netflow_engine_type = netflow_engine_type;
> -- 
> 2.30.2



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