Commit 46126db9 authored by Wojciech Drewek's avatar Wojciech Drewek Committed by Tony Nguyen
Browse files

flow_dissector: Add PPPoE dissectors 



Allow to dissect PPPoE specific fields which are:
- session ID (16 bits)
- ppp protocol (16 bits)
- type (16 bits) - this is PPPoE ethertype, for now only
  ETH_P_PPP_SES is supported, possible ETH_P_PPP_DISC
  in the future

The goal is to make the following TC command possible:

  # tc filter add dev ens6f0 ingress prio 1 protocol ppp_ses \
      flower \
        pppoe_sid 12 \
        ppp_proto ip \
      action drop

Note that only PPPoE Session is supported.

Signed-off-by: default avatarWojciech Drewek <wojciech.drewek@intel.com>
Acked-by: default avatarGuillaume Nault <gnault@redhat.com>
Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
parent 35d099da

include/linux/ppp_defs.h

+14 −0
Original line number Diff line number Diff line
@@ -11,4 +11,18 @@ 
#include <uapi/linux/ppp_defs.h>



#define PPP_FCS(fcs, c) crc_ccitt_byte(fcs, c)



/**

 * ppp_proto_is_valid - checks if PPP protocol is valid

 * @proto: PPP protocol

 *

 * Assumes proto is not compressed.

 * Protocol is valid if the value is odd and the least significant bit of the

 * most significant octet is 0 (see RFC 1661, section 2).

 */

static inline bool ppp_proto_is_valid(u16 proto)

{

	return !!((proto & 0x0101) == 0x0001);

}



#endif /* _PPP_DEFS_H_ */

include/net/flow_dissector.h

+13 −0
Original line number Diff line number Diff line
@@ -277,6 +277,18 @@ struct flow_dissector_key_num_of_vlans { 
	u8 num_of_vlans;

};



/**

 * struct flow_dissector_key_pppoe:

 * @session_id: pppoe session id

 * @ppp_proto: ppp protocol

 * @type: pppoe eth type

 */

struct flow_dissector_key_pppoe {

	__be16 session_id;

	__be16 ppp_proto;

	__be16 type;

};



enum flow_dissector_key_id {

	FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */

	FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
@@ -307,6 +319,7 @@ enum flow_dissector_key_id { 
	FLOW_DISSECTOR_KEY_CT, /* struct flow_dissector_key_ct */

	FLOW_DISSECTOR_KEY_HASH, /* struct flow_dissector_key_hash */

	FLOW_DISSECTOR_KEY_NUM_OF_VLANS, /* struct flow_dissector_key_num_of_vlans */

	FLOW_DISSECTOR_KEY_PPPOE, /* struct flow_dissector_key_pppoe */



	FLOW_DISSECTOR_KEY_MAX,

};

net/core/flow_dissector.c

+46 −7
Original line number Diff line number Diff line
@@ -895,6 +895,11 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, 
	return result == BPF_OK;

}



static bool is_pppoe_ses_hdr_valid(struct pppoe_hdr hdr)

{

	return hdr.ver == 1 && hdr.type == 1 && hdr.code == 0;

}



/**

 * __skb_flow_dissect - extract the flow_keys struct and return it

 * @net: associated network namespace, derived from @skb if NULL
@@ -1214,26 +1219,60 @@ bool __skb_flow_dissect(const struct net *net, 
			struct pppoe_hdr hdr;

			__be16 proto;

		} *hdr, _hdr;

		u16 ppp_proto;



		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);

		if (!hdr) {

			fdret = FLOW_DISSECT_RET_OUT_BAD;

			break;

		}



		if (!is_pppoe_ses_hdr_valid(hdr->hdr)) {

			fdret = FLOW_DISSECT_RET_OUT_BAD;

			break;

		}



		/* least significant bit of the most significant octet

		 * indicates if protocol field was compressed

		 */

		ppp_proto = ntohs(hdr->proto);

		if (ppp_proto & 0x0100) {

			ppp_proto = ppp_proto >> 8;

			nhoff += PPPOE_SES_HLEN - 1;

		} else {

			nhoff += PPPOE_SES_HLEN;

		switch (hdr->proto) {

		case htons(PPP_IP):

		}



		if (ppp_proto == PPP_IP) {

			proto = htons(ETH_P_IP);

			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;

			break;

		case htons(PPP_IPV6):

		} else if (ppp_proto == PPP_IPV6) {

			proto = htons(ETH_P_IPV6);

			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;

			break;

		default:

		} else if (ppp_proto == PPP_MPLS_UC) {

			proto = htons(ETH_P_MPLS_UC);

			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;

		} else if (ppp_proto == PPP_MPLS_MC) {

			proto = htons(ETH_P_MPLS_MC);

			fdret = FLOW_DISSECT_RET_PROTO_AGAIN;

		} else if (ppp_proto_is_valid(ppp_proto)) {

			fdret = FLOW_DISSECT_RET_OUT_GOOD;

		} else {

			fdret = FLOW_DISSECT_RET_OUT_BAD;

			break;

		}



		if (dissector_uses_key(flow_dissector,

				       FLOW_DISSECTOR_KEY_PPPOE)) {

			struct flow_dissector_key_pppoe *key_pppoe;



			key_pppoe = skb_flow_dissector_target(flow_dissector,

							      FLOW_DISSECTOR_KEY_PPPOE,

							      target_container);

			key_pppoe->session_id = hdr->hdr.sid;

			key_pppoe->ppp_proto = htons(ppp_proto);

			key_pppoe->type = htons(ETH_P_PPP_SES);

		}

		break;

	}

	case htons(ETH_P_TIPC): {