Introduce PPPoE specific fields in tc-flower:
- session id (16 bits)
- ppp protocol (16 bits)
Those fields can be provided only when protocol was set to
ETH_P_PPP_SES. ppp_proto works similar to vlan_ethtype, i.e.
ppp_proto overwrites eth_type. Thanks to that, fields from
encapsulated protocols (such as src_ip) can be specified.

e.g.
  # tc filter add dev ens6f0 ingress prio 1 protocol ppp_ses \
      flower \
        pppoe_sid 1234 \
        ppp_proto ip \
        dst_ip 127.0.0.1 \
        src_ip 127.0.0.2 \
      action drop

Vlan and cvlan is also supported, in this case cvlan_ethtype
or vlan_ethtype has to be set to ETH_P_PPP_SES.

e.g.
  # tc filter add dev ens6f0 ingress prio 1 protocol 802.1Q \
      flower \
        vlan_id 2 \
        vlan_ethtype ppp_ses \
        pppoe_sid 1234 \
        ppp_proto ip \
        dst_ip 127.0.0.1 \
        src_ip 127.0.0.2 \
      action drop

Signed-off-by: Wojciech Drewek <redacted>
---
v2: add pppoe fields to explain
---
 include/uapi/linux/pkt_cls.h |  3 ++
 man/man8/tc-flower.8         | 17 ++++++++++-
 tc/f_flower.c                | 58 ++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index 9a2ee1e39fad..a67dcd8294c9 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h

@@ -589,6 +589,9 @@ enum {
 
 	TCA_FLOWER_KEY_NUM_OF_VLANS,    /* u8 */
 
+	TCA_FLOWER_KEY_PPPOE_SID,	/* u16 */
+	TCA_FLOWER_KEY_PPP_PROTO,	/* be16 */
+
 	__TCA_FLOWER_MAX,
 };
 

diff --git a/man/man8/tc-flower.8 b/man/man8/tc-flower.8
index 523935242ccf..5e486ea31d37 100644
--- a/man/man8/tc-flower.8
+++ b/man/man8/tc-flower.8

@@ -40,6 +40,10 @@ flower \- flow based traffic control filter
 .IR PRIORITY " | "
 .BR cvlan_ethtype " { " ipv4 " | " ipv6 " | "
 .IR ETH_TYPE " } | "
+.B pppoe_sid
+.IR PSID " | "
+.BR ppp_proto " { " ip " | " ipv6 " | " mpls_uc " | " mpls_mc " | "
+.IR PPP_PROTO " } | "
 .B mpls
 .IR LSE_LIST " | "
 .B mpls_label

@@ -202,7 +206,18 @@ Match on QinQ layer three protocol.
 may be either
 .BR ipv4 ", " ipv6
 or an unsigned 16bit value in hexadecimal format.
-
+.TP
+.BI pppoe_sid " PSID"
+Match on PPPoE session id.
+.I PSID
+is an unsigned 16bit value in decimal format.
+.TP
+.BI ppp_proto " PPP_PROTO"
+Match on PPP layer three protocol.
+.I PPP_PROTO
+may be either
+.BR ip ", " ipv6 ", " mpls_uc ", " mpls_mc
+or an unsigned 16bit value in hexadecimal format.
 .TP
 .BI mpls " LSE_LIST"
 Match on the MPLS label stack.

diff --git a/tc/f_flower.c b/tc/f_flower.c
index 622ec321f310..c95320328b20 100644
--- a/tc/f_flower.c
+++ b/tc/f_flower.c

@@ -20,6 +20,7 @@
 #include <linux/ip.h>
 #include <linux/tc_act/tc_vlan.h>
 #include <linux/mpls.h>
+#include <linux/ppp_defs.h>
 
 #include "utils.h"
 #include "tc_util.h"

@@ -55,6 +56,8 @@ static void explain(void)
 		"			cvlan_id VID |\n"
 		"			cvlan_prio PRIORITY |\n"
 		"			cvlan_ethtype [ ipv4 | ipv6 | ETH-TYPE ] |\n"
+		"			pppoe_sid PSID |\n"
+		"			ppp_proto [ ipv4 | ipv6 | mpls_uc | mpls_mc | PPP_PROTO ]"
 		"			dst_mac MASKED-LLADDR |\n"
 		"			src_mac MASKED-LLADDR |\n"
 		"			ip_proto [tcp | udp | sctp | icmp | icmpv6 | IP-PROTO ] |\n"

@@ -1887,6 +1890,43 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 				fprintf(stderr, "Illegal \"arp_sha\"\n");
 				return -1;
 			}
+
+		} else if (!strcmp(*argv, "pppoe_sid")) {
+			__be16 sid;
+
+			NEXT_ARG();
+			if (eth_type != htons(ETH_P_PPP_SES)) {
+				fprintf(stderr,
+					"Can't set \"pppoe_sid\" if ethertype isn't PPPoE session\n");
+				return -1;
+			}
+			ret = get_be16(&sid, *argv, 10);
+			if (ret < 0 || sid == 0xffff) {
+				fprintf(stderr, "Illegal \"pppoe_sid\"\n");