[ovs-dev] [PATCH RFC v2 3/8] tc: Introduce tc_id to specify a tc filter

Simon Horman simon.horman at netronome.com
Fri Jul 26 09:47:49 UTC 2019


Hi Paul,

On Thu, Jul 04, 2019 at 05:28:22PM +0300, Paul Blakey wrote:
> Move all that is needed to identify a tc filter to a
> new structure, tc_id. This removes a lot of duplication
> in accessing/creating tc filters.
> 
> Signed-off-by: Paul Blakey <paulb at mellanox.com>

This is a rather large patch.
I'm wondering if you could comment on how thoroughly it has
been tested.

> ---
>  lib/netdev-linux.c      |   6 +-
>  lib/netdev-offload-tc.c | 207 ++++++++++++++++++++----------------------------
>  lib/tc.c                | 122 +++++++++++-----------------
>  lib/tc.h                |  28 ++++---
>  4 files changed, 151 insertions(+), 212 deletions(-)
> 
> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
> index e4ea94c..69e0982 100644
> --- a/lib/netdev-linux.c
> +++ b/lib/netdev-linux.c
> @@ -2421,6 +2421,8 @@ static int
>  tc_del_matchall_policer(struct netdev *netdev)
>  {
>      uint32_t block_id = 0;
> +    int prio = TC_RESERVED_PRIORITY_POLICE;
> +    struct tc_id id;
>      int ifindex;
>      int err;
>  
> @@ -2429,8 +2431,8 @@ tc_del_matchall_policer(struct netdev *netdev)
>          return err;
>      }
>  
> -    err = tc_del_filter(ifindex, TC_RESERVED_PRIORITY_POLICE, 1, block_id,
> -                        TC_INGRESS);
> +    id = make_tc_id(ifindex, block_id, prio, TC_INGRESS);
> +    err = tc_del_filter(&id);
>      if (err) {
>          return err;
>      }
> diff --git a/lib/netdev-offload-tc.c b/lib/netdev-offload-tc.c
> index 2af0f10..e37049c 100644
> --- a/lib/netdev-offload-tc.c
> +++ b/lib/netdev-offload-tc.c
> @@ -145,20 +145,16 @@ static struct ovs_mutex ufid_lock = OVS_MUTEX_INITIALIZER;
>  /**
>   * struct ufid_tc_data - data entry for ufid_tc hmap.
>   * @ufid_node: Element in @ufid_tc hash table by ufid key.
> - * @tc_node: Element in @ufid_tc hash table by prio/handle/ifindex key.
> + * @tc_node: Element in @ufid_tc hash table by tc_id key.
>   * @ufid: ufid assigned to the flow
> - * @prio: tc priority
> - * @handle: tc handle
> - * @ifindex: netdev ifindex.
> + * @id: tc id
>   * @netdev: netdev associated with the tc rule
>   */
>  struct ufid_tc_data {
>      struct hmap_node ufid_node;
>      struct hmap_node tc_node;
>      ovs_u128 ufid;
> -    uint16_t prio;
> -    uint32_t handle;
> -    int ifindex;
> +    struct tc_id id;
>      struct netdev *netdev;
>  };
>  
> @@ -190,32 +186,27 @@ del_ufid_tc_mapping(const ovs_u128 *ufid)
>  
>  /* Wrapper function to delete filter and ufid tc mapping */
>  static int
> -del_filter_and_ufid_mapping(int ifindex, int prio, int handle,
> -                            uint32_t block_id, const ovs_u128 *ufid,
> -                            enum tc_qdisc_hook hook)
> +del_filter_and_ufid_mapping(struct tc_id *id, const ovs_u128 *ufid)
>  {
>      int err;
>  
> -    err = tc_del_filter(ifindex, prio, handle, block_id, hook);
> +    err = tc_del_filter(id);
>      del_ufid_tc_mapping(ufid);
> -
>      return err;
>  }
>  
>  /* Add ufid entry to ufid_tc hashmap. */
>  static void
> -add_ufid_tc_mapping(const ovs_u128 *ufid, int prio, int handle,
> -                    struct netdev *netdev, int ifindex)
> +add_ufid_tc_mapping(struct netdev *netdev, const ovs_u128 *ufid,
> +                    struct tc_id *id)

Adding the id parameter after the ufid parameter does not
seem consistent with some other functions, f.e. find_ufid(),
while consistent with others, f.e. get_ufid_tc_mapping().

Could a more consistent parameter ordering be used throughout
this patch?

>  {
>      size_t ufid_hash = hash_bytes(ufid, sizeof *ufid, 0);
> -    size_t tc_hash = hash_int(hash_int(prio, handle), ifindex);
> +    size_t tc_hash = hash_int(hash_int(id->prio, id->handle), id->ifindex);
>      struct ufid_tc_data *new_data = xzalloc(sizeof *new_data);
>  
>      new_data->ufid = *ufid;
> -    new_data->prio = prio;
> -    new_data->handle = handle;
> +    new_data->id = *id;
>      new_data->netdev = netdev_ref(netdev);
> -    new_data->ifindex = ifindex;
>  
>      ovs_mutex_lock(&ufid_lock);
>      hmap_insert(&ufid_tc, &new_data->ufid_node, ufid_hash);
> @@ -223,56 +214,49 @@ add_ufid_tc_mapping(const ovs_u128 *ufid, int prio, int handle,
>      ovs_mutex_unlock(&ufid_lock);
>  }
>  
> -/* Get ufid from ufid_tc hashmap.
> +/* Get tc id from ufid_tc hashmap.
>   *
> - * If netdev output param is not NULL then the function will return
> - * associated netdev on success and a refcount is taken on that netdev.
> - * The caller is then responsible to close the netdev.
> - *
> - * Returns handle if successful and fill prio and netdev for that ufid.
> - * Otherwise returns 0.
> + * Returns 0 if successful and fills id.
> + * Otherwise returns the error.
>   */
>  static int
> -get_ufid_tc_mapping(const ovs_u128 *ufid, int *prio, struct netdev **netdev)
> +get_ufid_tc_mapping(const ovs_u128 *ufid, struct tc_id *id)
>  {
>      size_t ufid_hash = hash_bytes(ufid, sizeof *ufid, 0);
>      struct ufid_tc_data *data;
> -    int handle = 0;
>  
>      ovs_mutex_lock(&ufid_lock);
>      HMAP_FOR_EACH_WITH_HASH(data, ufid_node, ufid_hash, &ufid_tc) {
>          if (ovs_u128_equals(*ufid, data->ufid)) {
> -            if (prio) {
> -                *prio = data->prio;
> -            }
> -            if (netdev) {
> -                *netdev = netdev_ref(data->netdev);
> -            }
> -            handle = data->handle;
> -            break;
> +            *id = data->id;

Did you consider returning &data-id (or NULL on error)?

As this function now only returns one value (id) rather than two
(prio and netdev) returning a reference to the id may be cleaner.

> +            ovs_mutex_unlock(&ufid_lock);
> +            return 0;
>          }
>      }
>      ovs_mutex_unlock(&ufid_lock);
>  
> -    return handle;
> +    return ENOENT;
>  }
>  
> -/* Find ufid entry in ufid_tc hashmap using prio, handle and netdev.
> +/* Find ufid entry in ufid_tc hashmap using tc_id id.
>   * The result is saved in ufid.
>   *
>   * Returns true on success.
>   */
>  static bool
> -find_ufid(int prio, int handle, struct netdev *netdev, ovs_u128 *ufid)
> +find_ufid(struct netdev *netdev, struct tc_id *id, ovs_u128 *ufid)

I think this could also return a reference to id.
But by that reasoning it could have also returned a reference before the id
change.  So perhaps I am missing something here.

>  {
> -    int ifindex = netdev_get_ifindex(netdev);
> +    size_t tc_hash = hash_int(hash_int(id->prio, id->handle), id->ifindex);
>      struct ufid_tc_data *data;
> -    size_t tc_hash = hash_int(hash_int(prio, handle), ifindex);
>  
>      ovs_mutex_lock(&ufid_lock);
>      HMAP_FOR_EACH_WITH_HASH(data, tc_node, tc_hash,  &ufid_tc) {
> -        if (data->prio == prio && data->handle == handle
> -            && data->ifindex == ifindex) {
> +        if (netdev == data->netdev
> +            && data->id.prio == id->prio
> +            && data->id.handle == id->handle
> +            && data->id.hook == id->hook
> +            && data->id.block_id == id->block_id
> +            && data->id.ifindex == id->ifindex) {
>              *ufid = data->ufid;
>              break;
>          }
> @@ -356,6 +340,8 @@ netdev_tc_flow_flush(struct netdev *netdev)
>      enum tc_qdisc_hook hook = get_tc_qdisc_hook(netdev);
>      int ifindex = netdev_get_ifindex(netdev);
>      uint32_t block_id = 0;
> +    struct tc_id id;
> +    int prio = 0;
>  
>      if (ifindex < 0) {
>          VLOG_ERR_RL(&error_rl, "flow_flush: failed to get ifindex for %s: %s",
> @@ -364,8 +350,8 @@ netdev_tc_flow_flush(struct netdev *netdev)
>      }
>  
>      block_id = get_block_id_from_netdev(netdev);
> -
> -    return tc_flush(ifindex, block_id, hook);
> +    id = make_tc_id(ifindex, block_id, prio, hook);
> +    return tc_del_filter(&id);
>  }
>  
>  static int
> @@ -375,6 +361,8 @@ netdev_tc_flow_dump_create(struct netdev *netdev,
>      enum tc_qdisc_hook hook = get_tc_qdisc_hook(netdev);
>      struct netdev_flow_dump *dump;
>      uint32_t block_id = 0;
> +    struct tc_id id;
> +    int prio = 0;
>      int ifindex;
>  
>      ifindex = netdev_get_ifindex(netdev);
> @@ -388,7 +376,9 @@ netdev_tc_flow_dump_create(struct netdev *netdev,
>      dump = xzalloc(sizeof *dump);
>      dump->nl_dump = xzalloc(sizeof *dump->nl_dump);
>      dump->netdev = netdev_ref(netdev);
> -    tc_dump_flower_start(ifindex, dump->nl_dump, block_id, hook);
> +
> +    id = make_tc_id(ifindex, block_id, prio, hook);
> +    tc_dump_flower_start(&id, dump->nl_dump);
>  
>      *dump_out = dump;
>  
> @@ -739,13 +729,18 @@ netdev_tc_flow_dump_next(struct netdev_flow_dump *dump,
>                           struct ofpbuf *rbuffer,
>                           struct ofpbuf *wbuffer)
>  {
> +    struct netdev *netdev = dump->netdev;
>      struct ofpbuf nl_flow;
> +    struct tc_id id;
> +
> +    id.hook = get_tc_qdisc_hook(netdev);
> +    id.block_id = get_block_id_from_netdev(netdev);
> +    id.ifindex = netdev_get_ifindex(netdev);
>  
>      while (nl_dump_next(dump->nl_dump, &nl_flow, rbuffer)) {
>          struct tc_flower flower;
> -        struct netdev *netdev = dump->netdev;
>  
> -        if (parse_netlink_to_tc_flower(&nl_flow, &flower)) {
> +        if (parse_netlink_to_tc_flower(&nl_flow, &id, &flower)) {
>              continue;
>          }
>  
> @@ -756,7 +751,7 @@ netdev_tc_flow_dump_next(struct netdev_flow_dump *dump,
>  
>          if (flower.act_cookie.len) {
>              *ufid = *((ovs_u128 *) flower.act_cookie.data);
> -        } else if (!find_ufid(flower.prio, flower.handle, netdev, ufid)) {
> +        } else if (!find_ufid(netdev, &id, ufid)) {
>              continue;
>          }
>  
> @@ -1098,9 +1093,9 @@ netdev_tc_flow_put(struct netdev *netdev, struct match *match,
>      struct tc_action *action;
>      uint32_t block_id = 0;
>      struct nlattr *nla;
> +    struct tc_id id;
>      size_t left;
>      int prio = 0;
> -    int handle;
>      int ifindex;
>      int err;
>  
> @@ -1352,35 +1347,32 @@ netdev_tc_flow_put(struct netdev *netdev, struct match *match,
>          }
>      }
>  
> -    block_id = get_block_id_from_netdev(netdev);
> -    handle = get_ufid_tc_mapping(ufid, &prio, NULL);
> -    if (handle && prio) {
> -        VLOG_DBG_RL(&rl, "updating old handle: %d prio: %d", handle, prio);
> -        del_filter_and_ufid_mapping(ifindex, prio, handle, block_id, ufid,
> -                                    hook);
> -    }
> -
> -    if (!prio) {
> -        prio = get_prio_for_tc_flower(&flower);
> -        if (prio == 0) {
> -            VLOG_ERR_RL(&rl, "couldn't get tc prio: %s", ovs_strerror(ENOSPC));
> -            return ENOSPC;
> -        }
> +    if (!get_ufid_tc_mapping(ufid, &id)) {
> +        VLOG_DBG_RL(&rl, "updating old handle: %d prio: %d",
> +                    id.handle, id.prio);
> +        del_filter_and_ufid_mapping(&id, ufid);
> +    }
> +
> +    prio = get_prio_for_tc_flower(&flower);
> +    if (prio == 0) {
> +        VLOG_ERR_RL(&rl, "couldn't get tc prio: %s", ovs_strerror(ENOSPC));
> +        return ENOSPC;
>      }
>  
>      flower.act_cookie.data = ufid;
>      flower.act_cookie.len = sizeof *ufid;
>  
> -    err = tc_replace_flower(ifindex, prio, handle, &flower, block_id, hook);
> +    id = make_tc_id(ifindex, block_id, prio, hook);
> +    err = tc_replace_flower(&id, &flower);
>      if (!err) {
> -        add_ufid_tc_mapping(ufid, flower.prio, flower.handle, netdev, ifindex);
> +        add_ufid_tc_mapping(netdev, ufid, &id);
>      }
>  
>      return err;
>  }
>  
>  static int
> -netdev_tc_flow_get(struct netdev *netdev OVS_UNUSED,
> +netdev_tc_flow_get(struct netdev *netdev,
>                     struct match *match,
>                     struct nlattr **actions,
>                     const ovs_u128 *ufid,
> @@ -1389,43 +1381,27 @@ netdev_tc_flow_get(struct netdev *netdev OVS_UNUSED,
>                     struct ofpbuf *buf)
>  {
>      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
> -    struct netdev *dev;
>      struct tc_flower flower;
> -    enum tc_qdisc_hook hook;
> -    uint32_t block_id = 0;
>      odp_port_t in_port;
> -    int prio = 0;
> -    int ifindex;
> -    int handle;
> +    struct tc_id id;
>      int err;
>  
> -    handle = get_ufid_tc_mapping(ufid, &prio, &dev);
> -    if (!handle) {
> -        return ENOENT;
> -    }
> -
> -    hook = get_tc_qdisc_hook(dev);
> -
> -    ifindex = netdev_get_ifindex(dev);
> -    if (ifindex < 0) {
> -        VLOG_ERR_RL(&error_rl, "flow_get: failed to get ifindex for %s: %s",
> -                    netdev_get_name(dev), ovs_strerror(-ifindex));
> -        netdev_close(dev);
> -        return -ifindex;
> +    err = get_ufid_tc_mapping(ufid, &id);
> +    if (err) {
> +        return err;
>      }
>  
> -    block_id = get_block_id_from_netdev(dev);
>      VLOG_DBG_RL(&rl, "flow get (dev %s prio %d handle %d block_id %d)",
> -                netdev_get_name(dev), prio, handle, block_id);
> -    err = tc_get_flower(ifindex, prio, handle, &flower, block_id, hook);
> -    netdev_close(dev);
> +                netdev_get_name(netdev), id.prio, id.handle, id.block_id);
> +
> +    err = tc_get_flower(&id, &flower);
>      if (err) {
>          VLOG_ERR_RL(&error_rl, "flow get failed (dev %s prio %d handle %d): %s",
> -                    netdev_get_name(dev), prio, handle, ovs_strerror(err));
> +                    netdev_get_name(netdev), id.prio, id.handle, ovs_strerror(err));
>          return err;
>      }
>  
> -    in_port = netdev_ifindex_to_odp_port(ifindex);
> +    in_port = netdev_ifindex_to_odp_port(id.ifindex);
>      parse_tc_flower_to_match(&flower, match, actions, stats, attrs, buf);
>  
>      match->wc.masks.in_port.odp_port = u32_to_odp(UINT32_MAX);
> @@ -1440,44 +1416,24 @@ netdev_tc_flow_del(struct netdev *netdev OVS_UNUSED,
>                     struct dpif_flow_stats *stats)
>  {
>      struct tc_flower flower;
> -    enum tc_qdisc_hook hook;
> -    uint32_t block_id = 0;
> -    struct netdev *dev;
> -    int prio = 0;
> -    int ifindex;
> -    int handle;
> +    struct tc_id id;
>      int error;
>  
> -    handle = get_ufid_tc_mapping(ufid, &prio, &dev);
> -    if (!handle) {
> -        return ENOENT;
> -    }
> -
> -    hook = get_tc_qdisc_hook(dev);
> -
> -    ifindex = netdev_get_ifindex(dev);
> -    if (ifindex < 0) {
> -        VLOG_ERR_RL(&error_rl, "flow_del: failed to get ifindex for %s: %s",
> -                    netdev_get_name(dev), ovs_strerror(-ifindex));
> -        netdev_close(dev);
> -        return -ifindex;
> +    error = get_ufid_tc_mapping(ufid, &id);
> +    if (error) {
> +        return error;
>      }
>  
> -    block_id = get_block_id_from_netdev(dev);
> -
>      if (stats) {
>          memset(stats, 0, sizeof *stats);
> -        if (!tc_get_flower(ifindex, prio, handle, &flower, block_id, hook)) {
> +        if (!tc_get_flower(&id, &flower)) {
>              stats->n_packets = get_32aligned_u64(&flower.stats.n_packets);
>              stats->n_bytes = get_32aligned_u64(&flower.stats.n_bytes);
>              stats->used = flower.lastused;
>          }
>      }
>  
> -    error = del_filter_and_ufid_mapping(ifindex, prio, handle, block_id, ufid,
> -                                        hook);
> -
> -    netdev_close(dev);
> +    error = del_filter_and_ufid_mapping(&id, ufid);
>  
>      return error;
>  }
> @@ -1486,7 +1442,9 @@ static void
>  probe_multi_mask_per_prio(int ifindex)
>  {
>      struct tc_flower flower;
> +    struct tc_id id1, id2;
>      int block_id = 0;
> +    int prio = 1;
>      int error;
>  
>      error = tc_add_del_qdisc(ifindex, true, block_id, TC_INGRESS);
> @@ -1501,7 +1459,8 @@ probe_multi_mask_per_prio(int ifindex)
>      memset(&flower.key.dst_mac, 0x11, sizeof flower.key.dst_mac);
>      memset(&flower.mask.dst_mac, 0xff, sizeof flower.mask.dst_mac);
>  
> -    error = tc_replace_flower(ifindex, 1, 1, &flower, block_id, TC_INGRESS);
> +    id1 = make_tc_id(ifindex, block_id, prio, TC_INGRESS);
> +    error = tc_replace_flower(&id1, &flower);
>      if (error) {
>          goto out;
>      }
> @@ -1509,14 +1468,15 @@ probe_multi_mask_per_prio(int ifindex)
>      memset(&flower.key.src_mac, 0x11, sizeof flower.key.src_mac);
>      memset(&flower.mask.src_mac, 0xff, sizeof flower.mask.src_mac);
>  
> -    error = tc_replace_flower(ifindex, 1, 2, &flower, block_id, TC_INGRESS);
> -    tc_del_filter(ifindex, 1, 1, block_id, TC_INGRESS);
> +    id2 = make_tc_id(ifindex, block_id, prio, TC_INGRESS);
> +    error = tc_replace_flower(&id2, &flower);
> +    tc_del_filter(&id1);
>  
>      if (error) {
>          goto out;
>      }
>  
> -    tc_del_filter(ifindex, 1, 2, block_id, TC_INGRESS);
> +    tc_del_filter(&id2);
>  
>      multi_mask_per_prio = true;
>      VLOG_INFO("probe tc: multiple masks on single tc prio is supported.");
> @@ -1530,6 +1490,8 @@ probe_tc_block_support(int ifindex)
>  {
>      struct tc_flower flower;
>      uint32_t block_id = 1;
> +    struct tc_id id;
> +    int prio = 0;
>      int error;
>  
>      error = tc_add_del_qdisc(ifindex, true, block_id, TC_INGRESS);
> @@ -1544,7 +1506,8 @@ probe_tc_block_support(int ifindex)
>      memset(&flower.key.dst_mac, 0x11, sizeof flower.key.dst_mac);
>      memset(&flower.mask.dst_mac, 0xff, sizeof flower.mask.dst_mac);
>  
> -    error = tc_replace_flower(ifindex, 1, 1, &flower, block_id, TC_INGRESS);
> +    id = make_tc_id(ifindex, block_id, prio, TC_INGRESS);
> +    error = tc_replace_flower(&id, &flower);
>  
>      tc_add_del_qdisc(ifindex, false, block_id, TC_INGRESS);
>  
> diff --git a/lib/tc.c b/lib/tc.c
> index 1eca356..d7cb43e 100644
> --- a/lib/tc.c
> +++ b/lib/tc.c
> @@ -193,6 +193,21 @@ tc_make_request(int ifindex, int type, unsigned int flags,
>      return tcmsg;
>  }
>  
> +static void request_from_tc_id(struct tc_id *id, uint16_t eth_type,
> +                               int type, unsigned int flags,
> +                               struct ofpbuf *request)
> +{
> +    int ifindex = id->block_id ? TCM_IFINDEX_MAGIC_BLOCK : id->ifindex;
> +    struct tcmsg *tcmsg;
> +
> +    tcmsg = tc_make_request(ifindex, type, flags, request);
> +    tcmsg->tcm_parent = (id->hook == TC_EGRESS) ?
> +                        TC_EGRESS_PARENT : (id->block_id ? : TC_INGRESS_PARENT);
> +    tcmsg->tcm_info = tc_make_handle(id->prio, eth_type);
> +    tcmsg->tcm_handle = id->handle;
> +}


The above helper seems nice, leading to a good reduction in code
duplication. But I wonder if it would be nicer to add it in a earlier
patch in this series - for one it would make this patch shorter and
easier to review. But I do not feel strongly about this.

> +
> +
>  int
>  tc_transact(struct ofpbuf *request, struct ofpbuf **replyp)
>  {
> @@ -1429,7 +1444,8 @@ nl_parse_flower_options(struct nlattr *nl_options, struct tc_flower *flower)
>  }
>  
>  int
> -parse_netlink_to_tc_flower(struct ofpbuf *reply, struct tc_flower *flower)
> +parse_netlink_to_tc_flower(struct ofpbuf *reply, struct tc_id *id,
> +                           struct tc_flower *flower)
>  {
>      struct tcmsg *tc;
>      struct nlattr *ta[ARRAY_SIZE(tca_policy)];
> @@ -1442,16 +1458,17 @@ parse_netlink_to_tc_flower(struct ofpbuf *reply, struct tc_flower *flower)
>      memset(flower, 0, sizeof *flower);
>  
>      tc = ofpbuf_at_assert(reply, NLMSG_HDRLEN, sizeof *tc);
> -    flower->handle = tc->tcm_handle;
> +
>      flower->key.eth_type = (OVS_FORCE ovs_be16) tc_get_minor(tc->tcm_info);
>      flower->mask.eth_type = OVS_BE16_MAX;
> -    flower->prio = tc_get_major(tc->tcm_info);
> +    id->prio = tc_get_major(tc->tcm_info);
> +    id->handle = tc->tcm_handle;
>  
> -    if (flower->prio == TC_RESERVED_PRIORITY_POLICE) {
> +    if (id->prio == TC_RESERVED_PRIORITY_POLICE) {
>          return 0;
>      }
>  
> -    if (!flower->handle) {
> +    if (!id->handle) {
>          return EAGAIN;
>      }
>  
> @@ -1471,20 +1488,11 @@ parse_netlink_to_tc_flower(struct ofpbuf *reply, struct tc_flower *flower)
>  }
>  
>  int
> -tc_dump_flower_start(int ifindex, struct nl_dump *dump, uint32_t block_id,
> -                     enum tc_qdisc_hook hook)
> +tc_dump_flower_start(struct tc_id *id, struct nl_dump *dump)
>  {
>      struct ofpbuf request;
> -    struct tcmsg *tcmsg;
> -    int index;
> -
> -    index = block_id ? TCM_IFINDEX_MAGIC_BLOCK : ifindex;
> -    tcmsg = tc_make_request(index, RTM_GETTFILTER, NLM_F_DUMP, &request);
> -    tcmsg->tcm_parent = (hook == TC_EGRESS) ?
> -                        TC_EGRESS_PARENT : (block_id ? : TC_INGRESS_PARENT);
> -    tcmsg->tcm_info = TC_H_UNSPEC;
> -    tcmsg->tcm_handle = 0;
>  
> +    request_from_tc_id(id, 0, RTM_GETTFILTER, NLM_F_DUMP, &request);
>      nl_dump_start(dump, NETLINK_ROUTE, &request);
>      ofpbuf_uninit(&request);
>  
> @@ -1492,68 +1500,28 @@ tc_dump_flower_start(int ifindex, struct nl_dump *dump, uint32_t block_id,
>  }
>  
>  int
> -tc_flush(int ifindex, uint32_t block_id, enum tc_qdisc_hook hook)
> +tc_del_filter(struct tc_id *id)
>  {
>      struct ofpbuf request;
> -    struct tcmsg *tcmsg;
> -    int index;
> -
> -    index = block_id ? TCM_IFINDEX_MAGIC_BLOCK : ifindex;
> -    tcmsg = tc_make_request(index, RTM_DELTFILTER, NLM_F_ACK, &request);
> -    tcmsg->tcm_parent = (hook == TC_EGRESS) ?
> -                        TC_EGRESS_PARENT : (block_id ? : TC_INGRESS_PARENT);
> -    tcmsg->tcm_info = TC_H_UNSPEC;
>  
> +    request_from_tc_id(id, 0, RTM_DELTFILTER, NLM_F_ACK, &request);
>      return tc_transact(&request, NULL);
>  }
>  
>  int
> -tc_del_filter(int ifindex, int prio, int handle, uint32_t block_id,
> -              enum tc_qdisc_hook hook)
> -{
> -    struct ofpbuf request;
> -    struct tcmsg *tcmsg;
> -    struct ofpbuf *reply;
> -    int error;
> -    int index;
> -
> -    index = block_id ? TCM_IFINDEX_MAGIC_BLOCK : ifindex;
> -    tcmsg = tc_make_request(index, RTM_DELTFILTER, NLM_F_ECHO, &request);
> -    tcmsg->tcm_parent = (hook == TC_EGRESS) ?
> -                        TC_EGRESS_PARENT : (block_id ? : TC_INGRESS_PARENT);
> -    tcmsg->tcm_info = tc_make_handle(prio, 0);
> -    tcmsg->tcm_handle = handle;
> -
> -    error = tc_transact(&request, &reply);
> -    if (!error) {
> -        ofpbuf_delete(reply);
> -    }
> -    return error;
> -}
> -
> -int
> -tc_get_flower(int ifindex, int prio, int handle, struct tc_flower *flower,
> -              uint32_t block_id, enum tc_qdisc_hook hook)
> +tc_get_flower(struct tc_id *id, struct tc_flower *flower)
>  {
>      struct ofpbuf request;
> -    struct tcmsg *tcmsg;
>      struct ofpbuf *reply;
>      int error;
> -    int index;
> -
> -    index = block_id ? TCM_IFINDEX_MAGIC_BLOCK : ifindex;
> -    tcmsg = tc_make_request(index, RTM_GETTFILTER, NLM_F_ECHO, &request);
> -    tcmsg->tcm_parent = (hook == TC_EGRESS) ?
> -                        TC_EGRESS_PARENT : (block_id ? : TC_INGRESS_PARENT);
> -    tcmsg->tcm_info = tc_make_handle(prio, 0);
> -    tcmsg->tcm_handle = handle;
>  
> +    request_from_tc_id(id, 0, RTM_GETTFILTER, NLM_F_ECHO, &request);
>      error = tc_transact(&request, &reply);
>      if (error) {
>          return error;
>      }
>  
> -    error = parse_netlink_to_tc_flower(reply, flower);
> +    error = parse_netlink_to_tc_flower(reply, id, flower);
>      ofpbuf_delete(reply);
>      return error;
>  }
> @@ -2299,26 +2267,30 @@ nl_msg_put_flower_options(struct ofpbuf *request, struct tc_flower *flower)
>      return 0;
>  }
>  
> +struct tc_id make_tc_id(int ifindex, uint32_t block_id, uint16_t prio,
> +                        enum tc_qdisc_hook hook)
> +{
> +    struct tc_id id = { .handle = 0, };

Zeroing id does not seem strictly necessary if every field is set,
which seems to be the case.

> +
> +    id.ifindex = ifindex;
> +    id.block_id = block_id;
> +    id.prio = prio;
> +    id.hook = hook;
> +
> +    return id;

This is a very nice 'pure' function.
However I am concerned about any performance / stack overhead
of returning a structure by value. Did you give this some
consideration?

Perhaps this concern could be alleviated by making make_tc_id()
a static inline function. Just an idea.

> +}
> +
>  int
> -tc_replace_flower(int ifindex, uint16_t prio, uint32_t handle,
> -                  struct tc_flower *flower, uint32_t block_id,
> -                  enum tc_qdisc_hook hook)
> +tc_replace_flower(struct tc_id *id, struct tc_flower *flower)
>  {
>      struct ofpbuf request;
> -    struct tcmsg *tcmsg;
>      struct ofpbuf *reply;
>      int error = 0;
>      size_t basic_offset;
>      uint16_t eth_type = (OVS_FORCE uint16_t) flower->key.eth_type;
> -    int index;
>  
> -    index = block_id ? TCM_IFINDEX_MAGIC_BLOCK : ifindex;
> -    tcmsg = tc_make_request(index, RTM_NEWTFILTER, NLM_F_CREATE | NLM_F_ECHO,
> -                            &request);
> -    tcmsg->tcm_parent = (hook == TC_EGRESS) ?
> -                        TC_EGRESS_PARENT : (block_id ? : TC_INGRESS_PARENT);
> -    tcmsg->tcm_info = tc_make_handle(prio, eth_type);
> -    tcmsg->tcm_handle = handle;
> +    request_from_tc_id(id, eth_type, RTM_NEWTFILTER,
> +                       NLM_F_CREATE | NLM_F_ECHO, &request);
>  
>      nl_msg_put_string(&request, TCA_KIND, "flower");
>      basic_offset = nl_msg_start_nested(&request, TCA_OPTIONS);
> @@ -2337,8 +2309,8 @@ tc_replace_flower(int ifindex, uint16_t prio, uint32_t handle,
>          struct tcmsg *tc =
>              ofpbuf_at_assert(reply, NLMSG_HDRLEN, sizeof *tc);
>  
> -        flower->prio = tc_get_major(tc->tcm_info);
> -        flower->handle = tc->tcm_handle;
> +        id->prio = tc_get_major(tc->tcm_info);
> +        id->handle = tc->tcm_handle;
>          ofpbuf_delete(reply);
>      }
>  
> diff --git a/lib/tc.h b/lib/tc.h
> index 2e0f5e3..00acc41 100644
> --- a/lib/tc.h
> +++ b/lib/tc.h
> @@ -197,10 +197,18 @@ enum tc_offloaded_state {
>      TC_OFFLOADED_STATE_NOT_IN_HW,
>  };
>  
> -struct tc_flower {
> +struct tc_id {
> +    enum tc_qdisc_hook hook;
> +    uint32_t block_id;
> +    int ifindex;
> +    uint16_t prio;
>      uint32_t handle;
> -    uint32_t prio;
> +};

At a glance the ordering of the fields of struct tc_id
appears to result in a structure with holes on both 32bit and 64bit
architectures.

As this is an internal structure I think it would be worth
ordering the fields in a way that minimises holes.

>  
> +struct tc_id make_tc_id(int ifindex, uint32_t block_id, uint16_t prio,
> +                        enum tc_qdisc_hook hook);
> +
> +struct tc_flower {
>      struct tc_flower_key key;
>      struct tc_flower_key mask;
>  
> @@ -234,18 +242,12 @@ BUILD_ASSERT_DECL(offsetof(struct tc_flower, rewrite)
>                    + MEMBER_SIZEOF(struct tc_flower, rewrite)
>                    + sizeof(uint32_t) - 2 < sizeof(struct tc_flower));
>  
> -int tc_replace_flower(int ifindex, uint16_t prio, uint32_t handle,
> -                      struct tc_flower *flower, uint32_t block_id,
> -                      enum tc_qdisc_hook hook);
> -int tc_del_filter(int ifindex, int prio, int handle, uint32_t block_id,
> -                  enum tc_qdisc_hook hook);
> -int tc_get_flower(int ifindex, int prio, int handle,
> -                  struct tc_flower *flower, uint32_t block_id,
> -                  enum tc_qdisc_hook hook);
> -int tc_flush(int ifindex, uint32_t block_id, enum tc_qdisc_hook hook);
> -int tc_dump_flower_start(int ifindex, struct nl_dump *dump, uint32_t block_id,
> -                         enum tc_qdisc_hook hook);
> +int tc_replace_flower(struct tc_id *id, struct tc_flower *flower);
> +int tc_del_filter(struct tc_id *id);
> +int tc_get_flower(struct tc_id *id, struct tc_flower *flower);
> +int tc_dump_flower_start(struct tc_id *id, struct nl_dump *dump);
>  int parse_netlink_to_tc_flower(struct ofpbuf *reply,
> +                               struct tc_id *id,
>                                 struct tc_flower *flower);
>  void tc_set_policy(const char *policy);
>  
> -- 
> 1.8.3.1
> 


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