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sfc: support TC decap rules matching on enc_ip_tos
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Allow efx_tc_encap_match entries to include an ip_tos and ip_tos_mask.
To avoid partially-overlapping Outer Rules (which can lead to undefined
 behaviour in the hardware), store extra "pseudo" entries in our
 encap_match hashtable, which are used to enforce that all Outer Rule
 entries within a given <src_ip,dst_ip,udp_dport> tuple (or IPv6
 equivalent) have the same ip_tos_mask.
The "direct" encap_match entry takes a reference on the "pseudo",
 allowing it to be destroyed when all "direct" entries using it are
 removed.
efx_tc_em_pseudo_type is an enum rather than just a bool because in
 future an additional pseudo-type will be added to support Conntrack
 offload.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Edward Cree authored and David S. Miller committed May 12, 2023
1 parent 56beb35 commit 3c9561c
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Showing 2 changed files with 133 additions and 36 deletions.
145 changes: 109 additions & 36 deletions drivers/net/ethernet/sfc/tc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -202,6 +202,7 @@ static int efx_tc_flower_parse_match(struct efx_nic *efx,
BIT(FLOW_DISSECTOR_KEY_ENC_KEYID) |
BIT(FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) |
BIT(FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) |
BIT(FLOW_DISSECTOR_KEY_ENC_IP) |
BIT(FLOW_DISSECTOR_KEY_ENC_PORTS) |
BIT(FLOW_DISSECTOR_KEY_ENC_CONTROL) |
BIT(FLOW_DISSECTOR_KEY_TCP) |
Expand Down Expand Up @@ -346,20 +347,47 @@ static int efx_tc_flower_parse_match(struct efx_nic *efx,
return 0;
}

static void efx_tc_flower_release_encap_match(struct efx_nic *efx,
struct efx_tc_encap_match *encap)
{
int rc;

if (!refcount_dec_and_test(&encap->ref))
return; /* still in use */

if (encap->type == EFX_TC_EM_DIRECT) {
rc = efx_mae_unregister_encap_match(efx, encap);
if (rc)
/* Display message but carry on and remove entry from our
* SW tables, because there's not much we can do about it.
*/
netif_err(efx, drv, efx->net_dev,
"Failed to release encap match %#x, rc %d\n",
encap->fw_id, rc);
}
rhashtable_remove_fast(&efx->tc->encap_match_ht, &encap->linkage,
efx_tc_encap_match_ht_params);
if (encap->pseudo)
efx_tc_flower_release_encap_match(efx, encap->pseudo);
kfree(encap);
}

static int efx_tc_flower_record_encap_match(struct efx_nic *efx,
struct efx_tc_match *match,
enum efx_encap_type type,
enum efx_tc_em_pseudo_type em_type,
u8 child_ip_tos_mask,
struct netlink_ext_ack *extack)
{
struct efx_tc_encap_match *encap, *old;
struct efx_tc_encap_match *encap, *old, *pseudo = NULL;
bool ipv6 = false;
int rc;

/* We require that the socket-defining fields (IP addrs and UDP dest
* port) are present and exact-match. Other fields are currently not
* allowed. This meets what OVS will ask for, and means that we don't
* need to handle difficult checks for overlapping matches as could
* come up if we allowed masks or varying sets of match fields.
* port) are present and exact-match. Other fields may only be used
* if the field-set (and any masks) are the same for all encap
* matches on the same <sip,dip,dport> tuple; this is enforced by
* pseudo encap matches.
*/
if (match->mask.enc_dst_ip | match->mask.enc_src_ip) {
if (!IS_ALL_ONES(match->mask.enc_dst_ip)) {
Expand Down Expand Up @@ -402,21 +430,37 @@ static int efx_tc_flower_record_encap_match(struct efx_nic *efx,
return -EOPNOTSUPP;
}
if (match->mask.enc_ip_tos) {
NL_SET_ERR_MSG_MOD(extack, "Egress encap match on IP ToS not supported");
return -EOPNOTSUPP;
struct efx_tc_match pmatch = *match;

if (em_type == EFX_TC_EM_PSEUDO_MASK) { /* can't happen */
NL_SET_ERR_MSG_MOD(extack, "Bad recursion in egress encap match handler");
return -EOPNOTSUPP;
}
pmatch.value.enc_ip_tos = 0;
pmatch.mask.enc_ip_tos = 0;
rc = efx_tc_flower_record_encap_match(efx, &pmatch, type,
EFX_TC_EM_PSEUDO_MASK,
match->mask.enc_ip_tos,
extack);
if (rc)
return rc;
pseudo = pmatch.encap;
}
if (match->mask.enc_ip_ttl) {
NL_SET_ERR_MSG_MOD(extack, "Egress encap match on IP TTL not supported");
return -EOPNOTSUPP;
rc = -EOPNOTSUPP;
goto fail_pseudo;
}

rc = efx_mae_check_encap_match_caps(efx, ipv6, match->mask.enc_ip_tos, extack);
if (rc)
return rc;
goto fail_pseudo;

encap = kzalloc(sizeof(*encap), GFP_USER);
if (!encap)
return -ENOMEM;
if (!encap) {
rc = -ENOMEM;
goto fail_pseudo;
}
encap->src_ip = match->value.enc_src_ip;
encap->dst_ip = match->value.enc_dst_ip;
#ifdef CONFIG_IPV6
Expand All @@ -425,12 +469,56 @@ static int efx_tc_flower_record_encap_match(struct efx_nic *efx,
#endif
encap->udp_dport = match->value.enc_dport;
encap->tun_type = type;
encap->ip_tos = match->value.enc_ip_tos;
encap->ip_tos_mask = match->mask.enc_ip_tos;
encap->child_ip_tos_mask = child_ip_tos_mask;
encap->type = em_type;
encap->pseudo = pseudo;
old = rhashtable_lookup_get_insert_fast(&efx->tc->encap_match_ht,
&encap->linkage,
efx_tc_encap_match_ht_params);
if (old) {
/* don't need our new entry */
kfree(encap);
if (pseudo) /* don't need our new pseudo either */
efx_tc_flower_release_encap_match(efx, pseudo);
/* check old and new em_types are compatible */
switch (old->type) {
case EFX_TC_EM_DIRECT:
/* old EM is in hardware, so mustn't overlap with a
* pseudo, but may be shared with another direct EM
*/
if (em_type == EFX_TC_EM_DIRECT)
break;
NL_SET_ERR_MSG_MOD(extack, "Pseudo encap match conflicts with existing direct entry");
return -EEXIST;
case EFX_TC_EM_PSEUDO_MASK:
/* old EM is protecting a ToS-qualified filter, so may
* only be shared with another pseudo for the same
* ToS mask.
*/
if (em_type != EFX_TC_EM_PSEUDO_MASK) {
NL_SET_ERR_MSG_FMT_MOD(extack,
"%s encap match conflicts with existing pseudo(MASK) entry",
encap->type ? "Pseudo" : "Direct");
return -EEXIST;
}
if (child_ip_tos_mask != old->child_ip_tos_mask) {
NL_SET_ERR_MSG_FMT_MOD(extack,
"Pseudo encap match for TOS mask %#04x conflicts with existing pseudo(MASK) entry for TOS mask %#04x",
child_ip_tos_mask,
old->child_ip_tos_mask);
return -EEXIST;
}
break;
default: /* Unrecognised pseudo-type. Just say no */
NL_SET_ERR_MSG_FMT_MOD(extack,
"%s encap match conflicts with existing pseudo(%d) entry",
encap->type ? "Pseudo" : "Direct",
old->type);
return -EEXIST;
}
/* check old and new tun_types are compatible */
if (old->tun_type != type) {
NL_SET_ERR_MSG_FMT_MOD(extack,
"Egress encap match with conflicting tun_type %u != %u",
Expand All @@ -442,10 +530,12 @@ static int efx_tc_flower_record_encap_match(struct efx_nic *efx,
/* existing entry found */
encap = old;
} else {
rc = efx_mae_register_encap_match(efx, encap);
if (rc) {
NL_SET_ERR_MSG_MOD(extack, "Failed to record egress encap match in HW");
goto fail;
if (em_type == EFX_TC_EM_DIRECT) {
rc = efx_mae_register_encap_match(efx, encap);
if (rc) {
NL_SET_ERR_MSG_MOD(extack, "Failed to record egress encap match in HW");
goto fail;
}
}
refcount_set(&encap->ref, 1);
}
Expand All @@ -455,30 +545,12 @@ static int efx_tc_flower_record_encap_match(struct efx_nic *efx,
rhashtable_remove_fast(&efx->tc->encap_match_ht, &encap->linkage,
efx_tc_encap_match_ht_params);
kfree(encap);
fail_pseudo:
if (pseudo)
efx_tc_flower_release_encap_match(efx, pseudo);
return rc;
}

static void efx_tc_flower_release_encap_match(struct efx_nic *efx,
struct efx_tc_encap_match *encap)
{
int rc;

if (!refcount_dec_and_test(&encap->ref))
return; /* still in use */

rc = efx_mae_unregister_encap_match(efx, encap);
if (rc)
/* Display message but carry on and remove entry from our
* SW tables, because there's not much we can do about it.
*/
netif_err(efx, drv, efx->net_dev,
"Failed to release encap match %#x, rc %d\n",
encap->fw_id, rc);
rhashtable_remove_fast(&efx->tc->encap_match_ht, &encap->linkage,
efx_tc_encap_match_ht_params);
kfree(encap);
}

static void efx_tc_delete_rule(struct efx_nic *efx, struct efx_tc_flow_rule *rule)
{
efx_mae_delete_rule(efx, rule->fw_id);
Expand Down Expand Up @@ -632,6 +704,7 @@ static int efx_tc_flower_replace_foreign(struct efx_nic *efx,
}

rc = efx_tc_flower_record_encap_match(efx, &match, type,
EFX_TC_EM_DIRECT, 0,
extack);
if (rc)
goto release;
Expand Down
24 changes: 24 additions & 0 deletions drivers/net/ethernet/sfc/tc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,15 +74,39 @@ static inline bool efx_tc_match_is_encap(const struct efx_tc_match_fields *mask)
mask->enc_ip_ttl || mask->enc_sport || mask->enc_dport;
}

/**
* enum efx_tc_em_pseudo_type - &struct efx_tc_encap_match pseudo type
*
* These are used to classify "pseudo" encap matches, which don't refer
* to an entry in hardware but rather indicate that a section of the
* match space is in use by another Outer Rule.
*
* @EFX_TC_EM_DIRECT: real HW entry in Outer Rule table; not a pseudo.
* Hardware index in &struct efx_tc_encap_match.fw_id is valid.
* @EFX_TC_EM_PSEUDO_MASK: registered by an encap match which includes a
* match on an optional field (currently only ip_tos), to prevent an
* overlapping encap match _without_ optional fields.
* The pseudo encap match may be referenced again by an encap match
* with a different ip_tos value, but all ip_tos_mask must match the
* first (stored in our child_ip_tos_mask).
*/
enum efx_tc_em_pseudo_type {
EFX_TC_EM_DIRECT,
EFX_TC_EM_PSEUDO_MASK,
};

struct efx_tc_encap_match {
__be32 src_ip, dst_ip;
struct in6_addr src_ip6, dst_ip6;
__be16 udp_dport;
u8 ip_tos, ip_tos_mask;
struct rhash_head linkage;
enum efx_encap_type tun_type;
u8 child_ip_tos_mask;
refcount_t ref;
enum efx_tc_em_pseudo_type type;
u32 fw_id; /* index of this entry in firmware encap match table */
struct efx_tc_encap_match *pseudo; /* Referenced pseudo EM if needed */
};

struct efx_tc_match {
Expand Down

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