[ovs-dev] [PATCH V2 3/4] tc: Add header rewrite using tc pedit action

Simon Horman simon.horman at netronome.com
Mon Oct 30 13:42:43 UTC 2017


On Wed, Oct 25, 2017 at 02:24:15PM +0300, Roi Dayan wrote:
> 
> 
> On 27/09/2017 12:08, Simon Horman wrote:
> > On Mon, Sep 25, 2017 at 04:31:42PM +0300, Paul Blakey wrote:
> > > 
> > > 
> > > On 18/09/2017 18:01, Simon Horman wrote:
> > > > On Mon, Sep 18, 2017 at 07:16:03AM +0300, Roi Dayan wrote:
> > > > > From: Paul Blakey <paulb at mellanox.com>
> > > > > 
> > > > > To be later used to implement ovs action set offloading.
> > > > > 
> > > > > Signed-off-by: Paul Blakey <paulb at mellanox.com>
> > > > > Reviewed-by: Roi Dayan <roid at mellanox.com>
> > > > > ---
> > > > >   lib/tc.c | 372 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> > > > >   lib/tc.h |  16 +++
> > > > >   2 files changed, 385 insertions(+), 3 deletions(-)
> > > > > 
> > > > > diff --git a/lib/tc.c b/lib/tc.c
> > > > > index c9cada2..743b2ee 100644
> > > > > --- a/lib/tc.c
> > > > > +++ b/lib/tc.c
> > > > > @@ -21,8 +21,10 @@
> > > > >   #include <errno.h>
> > > > >   #include <linux/if_ether.h>
> > > > >   #include <linux/rtnetlink.h>
> > > > > +#include <linux/tc_act/tc_csum.h>
> > > > >   #include <linux/tc_act/tc_gact.h>
> > > > >   #include <linux/tc_act/tc_mirred.h>
> > > > > +#include <linux/tc_act/tc_pedit.h>
> > > > >   #include <linux/tc_act/tc_tunnel_key.h>
> > > > >   #include <linux/tc_act/tc_vlan.h>
> > > > >   #include <linux/gen_stats.h>
> > > > > @@ -33,11 +35,14 @@
> > > > >   #include "netlink-socket.h"
> > > > >   #include "netlink.h"
> > > > >   #include "openvswitch/ofpbuf.h"
> > > > > +#include "openvswitch/util.h"
> > > > >   #include "openvswitch/vlog.h"
> > > > >   #include "packets.h"
> > > > >   #include "timeval.h"
> > > > >   #include "unaligned.h"
> > > > > +#define MAX_PEDIT_OFFSETS 8
> > > > 
> > > > Why 8?
> > > We don't expect anything more right now (ipv6 src/dst rewrite requires 8
> > > pedits iirc). I can't think of a larger use case, maybe ipv6 + macs if
> > > that's makes sens. do you suggest we increase it? to what?
> > 
> > It seems strange to me to place a somewhat arbitrary small limit
> > when none exists in the pedit API being used. I would at prefer if
> > it was at least a bigger, say 16 or 32.
> 
> 
> Hi Simon,
> 
> Sorry for the late reply due to holidays and vacations.
> Me & Paul going to go over this and do the fixes needed and
> also rebase over latest master and run tests again.

Likewise, sorry for not responding earlier (same reason).

> I'll answer what I'm more familiar with now and Paul will continue.
> The 8 here is too low and you right. We used this definition
> for allocation of the pedit keys on the stack in
> nl_msg_put_flower_rewrite_pedits()
> 
> It was for convenience instead of calculating the maximum possible
> keys that could exists and allocating it there and freeing it at
> the end.
> 
> Increasing it to 32 is probably more than enough and wont waste much.

Thanks, that sounds good.

> > > > >   VLOG_DEFINE_THIS_MODULE(tc);
> > > > >   static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(60, 5);
> > > > > @@ -50,6 +55,82 @@ enum tc_offload_policy {
> > > > >   static enum tc_offload_policy tc_policy = TC_POLICY_NONE;
> > > > > +struct tc_pedit_key_ex {
> > > > > +    enum pedit_header_type htype;
> > > > > +    enum pedit_cmd cmd;
> > > > > +};
> > > > > +
> > > > > +struct flower_key_to_pedit {
> > > > > +    enum pedit_header_type htype;
> > > > > +    int flower_offset;
> > > > > +    int offset;
> > > > > +    int size;
> > > > > +};
> > > > > +
> > > > > +static struct flower_key_to_pedit flower_pedit_map[] = {
> > > > > +    {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_IP4,
> > > > > +        12,
> > > > > +        offsetof(struct tc_flower_key, ipv4.ipv4_src),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, ipv4.ipv4_src)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_IP4,
> > > > > +        16,
> > > > > +        offsetof(struct tc_flower_key, ipv4.ipv4_dst),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, ipv4.ipv4_dst)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_IP4,
> > > > > +        8,
> > > > > +        offsetof(struct tc_flower_key, ipv4.rewrite_ttl),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, ipv4.rewrite_ttl)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_IP6,
> > > > > +        8,
> > > > > +        offsetof(struct tc_flower_key, ipv6.ipv6_src),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, ipv6.ipv6_src)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_IP6,
> > > > > +        24,
> > > > > +        offsetof(struct tc_flower_key, ipv6.ipv6_dst),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, ipv6.ipv6_dst)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_ETH,
> > > > > +        6,
> > > > > +        offsetof(struct tc_flower_key, src_mac),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, src_mac)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_ETH,
> > > > > +        0,
> > > > > +        offsetof(struct tc_flower_key, dst_mac),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, dst_mac)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_ETH,
> > > > > +        12,
> > > > > +        offsetof(struct tc_flower_key, eth_type),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, eth_type)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_TCP,
> > > > > +        0,
> > > > > +        offsetof(struct tc_flower_key, tcp_src),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, tcp_src)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_TCP,
> > > > > +        2,
> > > > > +        offsetof(struct tc_flower_key, tcp_dst),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, tcp_dst)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_UDP,
> > > > > +        0,
> > > > > +        offsetof(struct tc_flower_key, udp_src),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, udp_src)
> > > > > +    }, {
> > > > > +        TCA_PEDIT_KEY_EX_HDR_TYPE_UDP,
> > > > > +        2,
> > > > > +        offsetof(struct tc_flower_key, udp_dst),
> > > > > +        MEMBER_SIZEOF(struct tc_flower_key, udp_dst)
> > > > > +    },
> > > > > +};
> > > > > +
> > > > >   struct tcmsg *
> > > > >   tc_make_request(int ifindex, int type, unsigned int flags,
> > > > >                   struct ofpbuf *request)
> > > > > @@ -365,6 +446,96 @@ nl_parse_flower_ip(struct nlattr **attrs, struct tc_flower *flower) {
> > > > >       }
> > > > >   }
> > > > > +static const struct nl_policy pedit_policy[] = {
> > > > > +            [TCA_PEDIT_PARMS_EX] = { .type = NL_A_UNSPEC,
> > > > > +                                     .min_len = sizeof(struct tc_pedit),
> > > > > +                                     .optional = false, },
> > > > > +            [TCA_PEDIT_KEYS_EX]   = { .type = NL_A_NESTED,
> > > > > +                                      .optional = false, },
> > > > > +};
> > > > > +
> > > > > +static int
> > > > > +nl_parse_act_pedit(struct nlattr *options, struct tc_flower *flower)
> > > > > +{
> > > > > +    struct nlattr *pe_attrs[ARRAY_SIZE(pedit_policy)];
> > > > > +    const struct tc_pedit *pe;
> > > > > +    const struct tc_pedit_key *keys;
> > > > > +    const struct nlattr *nla, *keys_ex, *ex_type;
> > > > > +    const void *keys_attr;
> > > > > +    char *rewrite_key = (void *) &flower->rewrite.key;
> > > > > +    char *rewrite_mask = (void *) &flower->rewrite.mask;
> > > > > +    size_t keys_ex_size, left;
> > > > > +    int type, i = 0;
> > > > > +
> > > > > +    if (!nl_parse_nested(options, pedit_policy, pe_attrs,
> > > > > +                         ARRAY_SIZE(pedit_policy))) {
> > > > > +        VLOG_ERR_RL(&error_rl, "failed to parse pedit action options");
> > > > > +        return EPROTO;
> > > > > +    }
> > > > > +
> > > > > +    pe = nl_attr_get_unspec(pe_attrs[TCA_PEDIT_PARMS_EX], sizeof *pe);
> > > > > +    keys = pe->keys;
> > > > > +    keys_attr = pe_attrs[TCA_PEDIT_KEYS_EX];
> > > > > +    keys_ex = nl_attr_get(keys_attr);
> > > > > +    keys_ex_size = nl_attr_get_size(keys_attr);
> > > > > +
> > > > > +    NL_ATTR_FOR_EACH (nla, left, keys_ex, keys_ex_size) {
> > > > > +        if (i >= pe->nkeys) {
> > > > > +            break;
> > > > > +        }
> > > > > +
> > > > > +        if (nl_attr_type(nla) == TCA_PEDIT_KEY_EX) {
> > > > > +            ex_type = nl_attr_find_nested(nla, TCA_PEDIT_KEY_EX_HTYPE);
> > > > > +            type = nl_attr_get_u16(ex_type);
> > > > > +
> > > > > +            for (int j = 0; j < ARRAY_SIZE(flower_pedit_map); j++) {
> > > > > +                struct flower_key_to_pedit *m = &flower_pedit_map[j];
> > > > > +                int flower_off = m->flower_offset;
> > > > > +                int sz = m->size;
> > > > > +                int mf = m->offset;
> > > > > +
> > > > > +                if (m->htype != type) {
> > > > > +                   continue;
> > > > > +                }
> > > > > +
> > > > > +                /* check overlap between current pedit key, which is always
> > > > > +                 * 4 bytes (range [off, off + 3]), and a map entry in
> > > > > +                 * flower_pedit_map (range [mf, mf + sz - 1]) */
> > > > > +                if ((keys->off >= mf && keys->off < mf + sz)
> > > > > +                    || (keys->off + 3 >= mf && keys->off + 3 < mf + sz)) {
> > > > > +                    int diff = flower_off + (keys->off - mf);
> > > > > +                    uint32_t *dst = (void *) (rewrite_key + diff);
> > > > > +                    uint32_t *dst_m = (void *) (rewrite_mask + diff);
> > > > > +                    uint32_t mask = ~(keys->mask);
> > > > > +                    uint32_t zero_bits;
> > > > > +
> > > > > +                    if (keys->off < mf) {
> > > > > +                        zero_bits = 8 * (mf - keys->off);
> > > > > +                        mask &= UINT32_MAX << zero_bits;
> > > > > +                    } else if (keys->off + 4 > mf + m->size) {
> > > > > +                        zero_bits = 8 * (keys->off + 4 - mf - m->size);
> > > > > +                        mask &= UINT32_MAX >> zero_bits;
> > > > > +                    }
> > > > > +
> > > > > +                    *dst_m |= mask;
> > > > > +                    *dst |= keys->val & mask;
> > > > > +                }
> > > > > +            }
> > > > 
> > > > If I understand the above correctly it is designed to make
> > > > pedit actions disjoint. If so, why is that necessary? >
> > > 
> > > It's not, as a single flower key rewrite can be split to multiple pedit
> > > actions it finds the overlap between a flower key and a pedit action, if
> > > they do overlap it translates it to the correct offset and masks it out.
> > 
> > Thanks, understood.
> > 
> > > 
> > > > > +        } else {
> > > > > +            VLOG_ERR_RL(&error_rl, "unable to parse legacy pedit type: %d",
> > > > > +                        nl_attr_type(nla));
> > > > > +            return EOPNOTSUPP;
> > > > > +        }
> > > > 
> > > > I think the code could exit early here as
> > > > nl_msg_put_flower_rewrite_pedits() does below.
> > > > 
> > > 
> > > Sorry, didn't understand. can you give an example?
> > > 
> > 
> > I meant something like this.
> > 
> >              if (nl_attr_type(nla) != TCA_PEDIT_KEY_EX) {
> >                  VLOG_ERR_RL(...);
> >                  return EOPNOTSUPP;
> >              }
> 
> understood. we'll do that. thanks.
> 
> > 
> > 	    /* Overlap detection code goes here */
> > 
> > > > 
> > > > > +
> > > > > +        keys++;
> > > > > +        i++;
> > > > > +    }
> > > > > +
> > > > > +    flower->rewrite.rewrite = true;
> > > > > +
> > > > > +    return 0;
> > > > > +}
> > > > > +
> > > > >   static const struct nl_policy tunnel_key_policy[] = {
> > > > >       [TCA_TUNNEL_KEY_PARMS] = { .type = NL_A_UNSPEC,
> > > > >                                  .min_len = sizeof(struct tc_tunnel_key),
> > > > > @@ -608,6 +779,11 @@ nl_parse_single_action(struct nlattr *action, struct tc_flower *flower)
> > > > >           nl_parse_act_vlan(act_options, flower);
> > > > >       } else if (!strcmp(act_kind, "tunnel_key")) {
> > > > >           nl_parse_act_tunnel_key(act_options, flower);
> > > > > +    } else if (!strcmp(act_kind, "pedit")) {
> > > > > +        nl_parse_act_pedit(act_options, flower);
> > > > > +    } else if (!strcmp(act_kind, "csum")) {
> > > > > +        /* not doing anything for now, ovs has an implicit csum recalculation
> > > > > +         * with rewriting of packet headers (translating of pedit acts). */
> > > > 
> > > > I wonder if the absence of a csum action when needed (by TC)
> > > > should be treated as an error >
> > > 
> > > Do you mean validating csum flags from each protocol and such (like in put)?
> > 
> > Yes, I think so.
> > 
> > In OvS (without TC acceleration) csum recalculation is implicit
> > but with TC an explicit csum update action is required. I see
> > in your code you are handling this by adding csum actions to TC actions
> > when translating from OvS DPIF actions. And in the reverse (above) csum
> > actions are simply ignored.
> > 
> > What I am wondering is if when translating TC actions to OvS DPIF actions
> > you should track if the TC actions should include a csum rule because
> > of other actions and treat its absence as an error.
> > 
> > > 
> > > > >       } else {
> > > > >           VLOG_ERR_RL(&error_rl, "unknown tc action kind: %s", act_kind);
> > > > >           return EINVAL;
> > > > > @@ -809,6 +985,48 @@ tc_get_tc_cls_policy(enum tc_offload_policy policy)
> > > > >   }
> > > > >   static void
> > > > > +nl_msg_put_act_csum(struct ofpbuf *request, uint32_t flags)
> > > > > +{
> > > > > +    size_t offset;
> > > > > +
> > > > > +    nl_msg_put_string(request, TCA_ACT_KIND, "csum");
> > > > > +    offset = nl_msg_start_nested(request, TCA_ACT_OPTIONS);
> > > > > +    {
> > > > > +        struct tc_csum parm = { .action = TC_ACT_PIPE,
> > > > > +                                .update_flags = flags };
> > > > > +
> > > > > +        nl_msg_put_unspec(request, TCA_CSUM_PARMS, &parm, sizeof parm);
> > > > > +    }
> > > > > +    nl_msg_end_nested(request, offset);
> > > > > +}
> > > > > +
> > > > > +static void
> > > > > +nl_msg_put_act_pedit(struct ofpbuf *request, struct tc_pedit *parm,
> > > > > +                     struct tc_pedit_key_ex *ex)
> > > > > +{
> > > > > +    size_t ksize = sizeof *parm + (parm->nkeys * sizeof(struct tc_pedit_key));
> > > > 
> > > > Are there unnecessary () on the line above?
> > > No, I'll remove them.
> > > 
> > > > 
> > > > > +    size_t offset, offset_keys_ex, offset_key;
> > > > > +    int i;
> > > > > +
> > > > > +    nl_msg_put_string(request, TCA_ACT_KIND, "pedit");
> > > > > +    offset = nl_msg_start_nested(request, TCA_ACT_OPTIONS);
> > > > > +    {
> > > > > +        parm->action = TC_ACT_PIPE;
> > > > > +
> > > > > +        nl_msg_put_unspec(request, TCA_PEDIT_PARMS_EX, parm, ksize);
> > > > > +        offset_keys_ex = nl_msg_start_nested(request, TCA_PEDIT_KEYS_EX);
> > > > > +        for (i = 0; i < parm->nkeys; i++, ex++) {
> > > > > +            offset_key = nl_msg_start_nested(request, TCA_PEDIT_KEY_EX);
> > > > > +            nl_msg_put_u16(request, TCA_PEDIT_KEY_EX_HTYPE, ex->htype);
> > > > > +            nl_msg_put_u16(request, TCA_PEDIT_KEY_EX_CMD, ex->cmd);
> > > > > +            nl_msg_end_nested(request, offset_key);
> > > > > +        }
> > > > > +        nl_msg_end_nested(request, offset_keys_ex);
> > > > > +    }
> > > > > +    nl_msg_end_nested(request, offset);
> > > > > +}
> > > > > +
> > > > > +static void
> > > > >   nl_msg_put_act_push_vlan(struct ofpbuf *request, uint16_t vid, uint8_t prio)
> > > > >   {
> > > > >       size_t offset;
> > > > > @@ -930,7 +1148,127 @@ nl_msg_put_act_cookie(struct ofpbuf *request, struct tc_cookie *ck) {
> > > > >       }
> > > > >   }
> > > > > +/* Given flower, a key_to_pedit map entry, calculates the rest,
> > > > > + * where:
> > > > > + *
> > > > > + * mask, data - pointers of where read the first word of flower->key/mask.
> > > > > + * current_offset - which offset to use for the first pedit action.
> > > > > + * cnt - max pedits actions to use.
> > > > > + * first_word_mask/last_word_mask - the mask to use for the first/last read
> > > > > + * (as we read entire words). */
> > > > >   static void
> > > > > +calc_offsets(struct tc_flower *flower, struct flower_key_to_pedit *m,
> > > > > +             int *cur_offset, int *cnt, uint32_t *last_word_mask,
> > > > > +             uint32_t *first_word_mask, uint32_t **mask, uint32_t **data)
> > > > > +{
> > > > > +    int start_offset, max_offset, total_size;
> > > > > +    int diff, right_zero_bits, left_zero_bits;
> > > > > +    char *rewrite_key = (void *) &flower->rewrite.key;
> > > > > +    char *rewrite_mask = (void *) &flower->rewrite.mask;
> > > > > +
> > > > > +    max_offset = m->offset + m->size;
> > > > > +    start_offset = ROUND_DOWN(m->offset, 4);
> > > > > +    diff = m->offset - start_offset;
> > > > > +    total_size = max_offset - start_offset;
> > > > > +    right_zero_bits = 8 * (4 - (max_offset % 4));
> > > > > +    left_zero_bits = 8 * (m->offset - start_offset);
> > > > > +
> > > > > +    *cur_offset = start_offset;
> > > > > +    *cnt = (total_size / 4) + (total_size % 4 ? 1 : 0);
> > > > > +    *last_word_mask = UINT32_MAX >> right_zero_bits;
> > > > > +    *first_word_mask = UINT32_MAX << left_zero_bits;
> > > > > +    *data = (void *) (rewrite_key + m->flower_offset - diff);
> > > > > +    *mask = (void *) (rewrite_mask + m->flower_offset - diff);
> > > > 
> > > > The type of *data and *mask is uint32_t *.
> > > > Why not cast to that type?
> > > 
> > > It's to avoid warning of increasing pointer alignment (-Wcast-align).
> > 
> > It sounds like the warning should be addressed rather than overridden using
> > a cast.
> > 
> > > > 
> > > > > +}
> > > > > +
> > > > > +static inline void
> > > > > +csum_update_flag(struct tc_flower *flower,
> > > > > +                 enum pedit_header_type htype) {
> > > > 
> > > > I think the above two lines could be one.
> > > > 
> > > > > +    if (htype == TCA_PEDIT_KEY_EX_HDR_TYPE_IP4) {
> > > > 
> > > > A case statement might be nicer here.
> > > 
> > > Right, thanks.
> > > 
> > > > 
> > > > > +        flower->csum_update_flags |= TCA_CSUM_UPDATE_FLAG_IPV4HDR;
> > > > > +    }
> > > > > +    if (htype == TCA_PEDIT_KEY_EX_HDR_TYPE_IP4
> > > > > +        || htype == TCA_PEDIT_KEY_EX_HDR_TYPE_IP6
> > > > > +        || htype == TCA_PEDIT_KEY_EX_HDR_TYPE_TCP
> > > > > +        || htype == TCA_PEDIT_KEY_EX_HDR_TYPE_UDP) {
> > > > > +        if (flower->key.ip_proto == IPPROTO_TCP) {
> > > > > +            flower->mask.ip_proto = UINT8_MAX;
> > > > 
> > > > What if the mask was not UINT8_MAX to start with?
> > > > Doesn't this create a different flow?
> > > 
> > > This is so the checksum will be strict (not setting/recalc udp checksum on
> > > non udp packets). It creates a more specific flow, a subset of the original.
> > > This is fine as datapath is free to ignore a mask, which is the same as a
> > > full mask we've set.
> > 
> > I'm not sure that I understand why its fine for the datapath to ignore the
> > mask.
> 
> I'll try to explain.
> When we want the HW to recalc the csum we need to also do matching on
> it. We do that for TCP, UDP, ICMP.

Ok, that makes sense. But I am concerned that the mask of the offloaded
flow no longer matches the mask of the flow OvS created. What are the
implications of that?

> > > > > +            flower->csum_update_flags |= TCA_CSUM_UPDATE_FLAG_TCP;
> > > > > +        } else if (flower->key.ip_proto == IPPROTO_UDP) {
> > > > > +            flower->mask.ip_proto = UINT8_MAX;
> > > > > +            flower->csum_update_flags |= TCA_CSUM_UPDATE_FLAG_UDP;
> > > > > +        } else if (flower->key.ip_proto == IPPROTO_ICMP
> > > > > +                   || flower->key.ip_proto == IPPROTO_ICMPV6) {
> > > > > +            flower->mask.ip_proto = UINT8_MAX;
> > > > > +            flower->csum_update_flags |= TCA_CSUM_UPDATE_FLAG_ICMP;
> > > > > +        }
> > > > > +    }
> > > > > +}
> > > > > +
> > > > > +static int
> > > > > +nl_msg_put_flower_rewrite_pedits(struct ofpbuf *request,
> > > > > +                                 struct tc_flower *flower)
> > > > > +{
> > > > > +    struct {
> > > > > +        struct tc_pedit sel;
> > > > > +        struct tc_pedit_key keys[MAX_PEDIT_OFFSETS];
> > > > > +        struct tc_pedit_key_ex keys_ex[MAX_PEDIT_OFFSETS];
> > > > > +    } sel = {
> > > > > +        .sel = {
> > > > > +            .nkeys = 0
> > > > > +        }
> > > > > +    };
> > > > > +    int i, j;
> > > > > +
> > > > > +    for (i = 0; i < ARRAY_SIZE(flower_pedit_map); i++) {
> > > > > +        struct flower_key_to_pedit *m = &flower_pedit_map[i];
> > > > > +        struct tc_pedit_key *pedit_key = NULL;
> > > > > +        struct tc_pedit_key_ex *pedit_key_ex = NULL;
> > > > > +        uint32_t *mask, *data, first_word_mask, last_word_mask;
> > > > > +        int cnt = 0, cur_offset = 0;
> > > > > +
> > > > > +        if (!m->size) {
> > > > > +            continue;
> > > > > +        }
> > > > > +
> > > > > +        calc_offsets(flower, m, &cur_offset, &cnt, &last_word_mask,
> > > > > +                     &first_word_mask, &mask, &data);
> > > > > +
> > > > > +        for (j = 0; j < cnt; j++,  mask++, data++, cur_offset += 4) {
> > > > > +            uint32_t mask_word = *mask;
> > > > > +
> > > > > +            if (j == 0) {
> > > > > +                mask_word &= first_word_mask;
> > > > > +            }
> > > > > +            if (j == cnt - 1) {
> > > > > +                mask_word &= last_word_mask;
> > > > > +            }
> > > > > +            if (!mask_word) {
> > > > > +                continue;
> > > > > +            }
> > > > > +            if (sel.sel.nkeys == MAX_PEDIT_OFFSETS) {
> > > > > +                VLOG_WARN_RL(&error_rl, "reached too many pedit offsets: %d",
> > > > > +                             MAX_PEDIT_OFFSETS);
> > > > > +                return EOPNOTSUPP;
> > > > > +            }
> > > > > +
> > > > > +            pedit_key = &sel.keys[sel.sel.nkeys];
> > > > > +            pedit_key_ex = &sel.keys_ex[sel.sel.nkeys];
> > > > > +            pedit_key_ex->cmd = TCA_PEDIT_KEY_EX_CMD_SET;
> > > > > +            pedit_key_ex->htype = m->htype;
> > > > > +            pedit_key->off = cur_offset;
> > > > > +            pedit_key->mask = ~mask_word;
> > > > > +            pedit_key->val = *data & mask_word;
> > > > > +            sel.sel.nkeys++;
> > > > > +            csum_update_flag(flower, m->htype);
> > > > > +        }
> > > > > +    }
> > > > > +    nl_msg_put_act_pedit(request, &sel.sel, sel.keys_ex);
> > > > > +
> > > > > +    return 0;
> > > > > +}
> > > > > +
> > > > > +static int
> > > > >   nl_msg_put_flower_acts(struct ofpbuf *request, struct tc_flower *flower)
> > > > >   {
> > > > >       size_t offset;
> > > > > @@ -939,7 +1277,20 @@ nl_msg_put_flower_acts(struct ofpbuf *request, struct tc_flower *flower)
> > > > >       offset = nl_msg_start_nested(request, TCA_FLOWER_ACT);
> > > > >       {
> > > > >           uint16_t act_index = 1;
> > > > > +        int error;
> > > > > +        if (flower->rewrite.rewrite) {
> > > > > +            act_offset = nl_msg_start_nested(request, act_index++);
> > > > > +            error = nl_msg_put_flower_rewrite_pedits(request, flower);
> > > > > +            if (error) {
> > > > > +                return error;
> > > > > +            }
> > > > > +            nl_msg_end_nested(request, act_offset);
> > > > > +
> > > > > +            act_offset = nl_msg_start_nested(request, act_index++);
> > > > > +            nl_msg_put_act_csum(request, flower->csum_update_flags);
> > > > > +            nl_msg_end_nested(request, act_offset);
> > > > > +        }
> > > > >           if (flower->set.set) {
> > > > >               act_offset = nl_msg_start_nested(request, act_index++);
> > > > >               nl_msg_put_act_tunnel_key_set(request, flower->set.id,
> > > > > @@ -980,6 +1331,8 @@ nl_msg_put_flower_acts(struct ofpbuf *request, struct tc_flower *flower)
> > > > >           }
> > > > >       }
> > > > >       nl_msg_end_nested(request, offset);
> > > > > +
> > > > > +    return 0;
> > > > >   }
> > > > >   static void
> > > > > @@ -1021,11 +1374,19 @@ nl_msg_put_flower_tunnel(struct ofpbuf *request, struct tc_flower *flower)
> > > > >       nl_msg_put_masked_value(request, type, type##_MASK, &flower->key.member, \
> > > > >                               &flower->mask.member, sizeof flower->key.member)
> > > > > -static void
> > > > > +static int
> > > > >   nl_msg_put_flower_options(struct ofpbuf *request, struct tc_flower *flower)
> > > > >   {
> > > > > +
> > > > >       uint16_t host_eth_type = ntohs(flower->key.eth_type);
> > > > >       bool is_vlan = (host_eth_type == ETH_TYPE_VLAN);
> > > > > +    int err;
> > > > > +
> > > > > +    /* need to parse acts first as some acts require changing the matching */
> > > > 
> > > > This seems strange to me.
> > > 
> > > from the strict (normalized?) header checksum.
> > 
> > I think this code relates to setting flower->key.ip_proto == IPPROTO_TCP
> > above. Is that correct. Are there any other cases?
> 
> yes and also for UDP and ICMP. as explained above.
> So going over the acts in header rewrite case we might want to signal the HW
> recalc csum and we need matching on those fields that require new
> csum so the matching mask being updated. this is why we parse the acts
> first.

Thanks, understood.

> > > > > +    err  = nl_msg_put_flower_acts(request, flower);
> > > > > +    if (err) {
> > > > > +        return err;
> > > > > +    }
> > > > >       if (is_vlan) {
> > > > >           host_eth_type = ntohs(flower->key.encap_eth_type);
> > > > > @@ -1083,7 +1444,7 @@ nl_msg_put_flower_options(struct ofpbuf *request, struct tc_flower *flower)
> > > > >           nl_msg_put_flower_tunnel(request, flower);
> > > > >       }
> > > > > -    nl_msg_put_flower_acts(request, flower);
> > > > > +    return 0;
> > > > >   }
> > > > >   int
> > > > > @@ -1106,7 +1467,12 @@ tc_replace_flower(int ifindex, uint16_t prio, uint32_t handle,
> > > > >       nl_msg_put_string(&request, TCA_KIND, "flower");
> > > > >       basic_offset = nl_msg_start_nested(&request, TCA_OPTIONS);
> > > > >       {
> > > > > -        nl_msg_put_flower_options(&request, flower);
> > > > > +        error = nl_msg_put_flower_options(&request, flower);
> > > > > +
> > > > > +        if (error) {
> > > > > +            ofpbuf_uninit(&request);
> > > > > +            return error;
> > > > > +        }
> > > > >       }
> > > > >       nl_msg_end_nested(&request, basic_offset);
> > > > > diff --git a/lib/tc.h b/lib/tc.h
> > > > > index 6c69b79..7876051 100644
> > > > > --- a/lib/tc.h
> > > > > +++ b/lib/tc.h
> > > > > @@ -96,6 +96,7 @@ struct tc_flower_key {
> > > > >       struct {
> > > > >           ovs_be32 ipv4_src;
> > > > >           ovs_be32 ipv4_dst;
> > > > > +        uint8_t rewrite_ttl;
> > > > >       } ipv4;
> > > > >       struct {
> > > > >           struct in6_addr ipv6_src;
> > > > > @@ -120,6 +121,14 @@ struct tc_flower {
> > > > >       uint64_t lastused;
> > > > >       struct {
> > > > > +        bool rewrite;
> > > > > +        struct tc_flower_key key;
> > > > > +        struct tc_flower_key mask;
> > > > > +    } rewrite;
> > > > > +
> > > > > +    uint32_t csum_update_flags;
> > > > > +
> > > > > +    struct {
> > > > >           bool set;
> > > > >           ovs_be64 id;
> > > > >           ovs_be16 tp_src;
> > > > > @@ -152,6 +161,13 @@ struct tc_flower {
> > > > >       struct tc_cookie act_cookie;
> > > > >   };
> > > > > +/* assert that if we overflow with a masked write of uint32_t to the last byte
> > > > > + * of flower.rewrite we overflow inside struct flower.
> > > > > + * shouldn't happen unless someone moves rewrite to the end of flower */
> > > > > +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);
> > > > >   int tc_del_filter(int ifindex, int prio, int handle);
> > > > > -- 
> > > > > 2.7.5
> > > > > 


More information about the dev mailing list