Re: [net-next PATCH V2] octeontx2-pf: Add support to filter packet based on IP fragment

[Alexander Lobakin]

From: Suman Ghosh <sumang@xxxxxxxxxxx>
Date: Wed, 23 Nov 2022 14:10:38 +0530

> 1. Added support to filter packets based on IP fragment.
> For IPv4 packets check for ip_flag == 0x20 (more fragment bit set).
> For IPv6 packets check for next_header == 0x2c (next_header set to
> 'fragment header for IPv6')
> 2. Added configuration support from both "ethtool ntuple" and "tc flower".
> 
> Signed-off-by: Suman Ghosh <sumang@xxxxxxxxxxx>
> ---
> Changes since v1:
> - Added extack change.
> - Added be32_to_cpu conversion for ip_flag mask also.
> 
>  .../net/ethernet/marvell/octeontx2/af/mbox.h  |  4 +++
>  .../net/ethernet/marvell/octeontx2/af/npc.h   |  2 ++
>  .../marvell/octeontx2/af/rvu_debugfs.c        |  8 ++++++
>  .../marvell/octeontx2/af/rvu_npc_fs.c         |  8 ++++++
>  .../marvell/octeontx2/nic/otx2_flows.c        | 25 ++++++++++++++++---
>  .../ethernet/marvell/octeontx2/nic/otx2_tc.c  | 25 +++++++++++++++++++
>  6 files changed, 68 insertions(+), 4 deletions(-)

[...]

> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
> index 642e58a04da0..1cf026de5f1a 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
> @@ -2799,6 +2799,14 @@ static void rvu_dbg_npc_mcam_show_flows(struct seq_file *s,
>  			seq_printf(s, "%pI6 ", rule->packet.ip6dst);
>  			seq_printf(s, "mask %pI6\n", rule->mask.ip6dst);
>  			break;
> +		case NPC_IPFRAG_IPV6:
> +			seq_printf(s, "%d ", rule->packet.next_header);
> +			seq_printf(s, "mask 0x%x\n", rule->mask.next_header);

Why the same field is printed as signed decimal in the first printf,
but as unsigned hex in the second? Could you please unify to `0x%x`?

> +			break;
> +		case NPC_IPFRAG_IPV4:
> +			seq_printf(s, "%d ", rule->packet.ip_flag);
> +			seq_printf(s, "mask 0x%x\n", rule->mask.ip_flag);

(same)

> +			break;
>  		case NPC_SPORT_TCP:
>  		case NPC_SPORT_UDP:
>  		case NPC_SPORT_SCTP:

[...]

> @@ -484,8 +486,10 @@ do {									       \
>  	 * Example: Source IP is 4 bytes and starts at 12th byte of IP header
>  	 */
>  	NPC_SCAN_HDR(NPC_TOS, NPC_LID_LC, NPC_LT_LC_IP, 1, 1);
> +	NPC_SCAN_HDR(NPC_IPFRAG_IPV4, NPC_LID_LC, NPC_LT_LC_IP, 6, 1);

I know it's out of the patch's subject, but this macro has "hidden"
argument usage:

* lid;
* lt;
* hdr;
* nr_bytes;
* mcam;
* cfg;
* intf;
* ...

We try to avoid that.
Could you please (in a separate patch, it can be made later)
refactor that block? For example, you can create an onstack
structure, put all those variables there and then pass that struct
to the macro.

Also, you call that macro 20+ times and it's not so small itself, so
converting these 20 calls to an array of 20 const parameters and
then doing one loop over that array can significantly reduce code
size.

>  	NPC_SCAN_HDR(NPC_SIP_IPV4, NPC_LID_LC, NPC_LT_LC_IP, 12, 4);
>  	NPC_SCAN_HDR(NPC_DIP_IPV4, NPC_LID_LC, NPC_LT_LC_IP, 16, 4);
> +	NPC_SCAN_HDR(NPC_IPFRAG_IPV6, NPC_LID_LC, NPC_LT_LC_IP6_EXT, 6, 1);
>  	NPC_SCAN_HDR(NPC_SIP_IPV6, NPC_LID_LC, NPC_LT_LC_IP6, 8, 16);
>  	NPC_SCAN_HDR(NPC_DIP_IPV6, NPC_LID_LC, NPC_LT_LC_IP6, 24, 16);
>  	NPC_SCAN_HDR(NPC_SPORT_UDP, NPC_LID_LD, NPC_LT_LD_UDP, 0, 2);
> @@ -899,6 +903,8 @@ do {									      \
>  	NPC_WRITE_FLOW(NPC_ETYPE, etype, ntohs(pkt->etype), 0,
>  		       ntohs(mask->etype), 0);
>  	NPC_WRITE_FLOW(NPC_TOS, tos, pkt->tos, 0, mask->tos, 0);
> +	NPC_WRITE_FLOW(NPC_IPFRAG_IPV4, ip_flag, pkt->ip_flag, 0,
> +		       mask->ip_flag, 0);

Same for this function.

>  	NPC_WRITE_FLOW(NPC_SIP_IPV4, ip4src, ntohl(pkt->ip4src), 0,
>  		       ntohl(mask->ip4src), 0);
>  	NPC_WRITE_FLOW(NPC_DIP_IPV4, ip4dst, ntohl(pkt->ip4dst), 0,
> @@ -919,6 +925,8 @@ do {									      \
>  	NPC_WRITE_FLOW(NPC_OUTER_VID, vlan_tci, ntohs(pkt->vlan_tci), 0,
>  		       ntohs(mask->vlan_tci), 0);
>  
> +	NPC_WRITE_FLOW(NPC_IPFRAG_IPV6, next_header, pkt->next_header, 0,
> +		       mask->next_header, 0);
>  	npc_update_ipv6_flow(rvu, entry, features, pkt, mask, output, intf);
>  	npc_update_vlan_features(rvu, entry, features, intf);

[...]

> -		/* Not Drop/Direct to queue but use action in default entry */
> -		if (fsp->m_ext.data[1] &&
> -		    fsp->h_ext.data[1] == cpu_to_be32(OTX2_DEFAULT_ACTION))
> -			req->op = NIX_RX_ACTION_DEFAULT;
> +		if (fsp->m_ext.data[1]) {
> +			if (flow_type == IP_USER_FLOW) {
> +				if (be32_to_cpu(fsp->h_ext.data[1]) != 0x20)

Define 0x20 as a macro to not search for it for long when it's
needed?

> +					return -EINVAL;
> +
> +				pkt->ip_flag = (u8)be32_to_cpu(fsp->h_ext.data[1]);
> +				pmask->ip_flag = (u8)be32_to_cpu(fsp->m_ext.data[1]);

These explicit casts are not needed unless I'm missing something?

> +				req->features |= BIT_ULL(NPC_IPFRAG_IPV4);
> +			} else if (fsp->h_ext.data[1] ==
> +					cpu_to_be32(OTX2_DEFAULT_ACTION)) {
> +				/* Not Drop/Direct to queue but use action
> +				 * in default entry
> +				 */
> +				req->op = NIX_RX_ACTION_DEFAULT;
> +			}
> +		}
>  	}
>  
>  	if (fsp->flow_type & FLOW_MAC_EXT &&
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
> index e64318c110fd..93b36d2cf883 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c
> @@ -532,6 +532,31 @@ static int otx2_tc_prepare_flow(struct otx2_nic *nic, struct otx2_tc_flow *node,
>  			req->features |= BIT_ULL(NPC_IPPROTO_ICMP6);
>  	}
>  
> +	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_CONTROL)) {
> +		struct flow_match_control match;
> +
> +		flow_rule_match_control(rule, &match);
> +		if (match.mask->flags & FLOW_DIS_FIRST_FRAG) {
> +			NL_SET_ERR_MSG_MOD(extack, "HW doesn't support frag first/later");
> +			return -EOPNOTSUPP;
> +		}
> +
> +		if (match.mask->flags & FLOW_DIS_IS_FRAGMENT) {
> +			if (ntohs(flow_spec->etype) == ETH_P_IP) {
> +				flow_spec->ip_flag = 0x20;

0x20 again, see? One definition for both would make it clear.

> +				flow_mask->ip_flag = 0xff;
> +				req->features |= BIT_ULL(NPC_IPFRAG_IPV4);
> +			} else if (ntohs(flow_spec->etype) == ETH_P_IPV6) {
> +				flow_spec->next_header = IPPROTO_FRAGMENT;
> +				flow_mask->next_header = 0xff;
> +				req->features |= BIT_ULL(NPC_IPFRAG_IPV6);
> +			} else {
> +				NL_SET_ERR_MSG_MOD(extack, "flow-type should be either IPv4 and IPv6");
> +				return -EOPNOTSUPP;
> +			}
> +		}
> +	}

This block is big and the function is huge even before the patch.
Could you (it may be a separate patch as well) split it logically?

> +
>  	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
>  		struct flow_match_eth_addrs match;
>  
> -- 
> 2.25.1

Thanks,
Olek