[RFC PATCH net-next v3 1/4] flow_dissector: Add PPPoE dissectors
From: Marcin Szycik <hidden>
Date: 2022-06-29 14:40:32
Also in:
intel-wired-lan
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Wojciech Drewek <redacted>
Allow to dissect PPPoE specific fields which are:
- session ID (16 bits)
- ppp protocol (16 bits)
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: Wojciech Drewek <redacted>
---
v3: revert byte order changes in is_ppp_proto_supported from previous
version, add kernel-doc for is_ppp_proto_supported
v2: use ntohs instead of htons in is_ppp_proto_supported
include/net/flow_dissector.h | 11 ++++++++
net/core/flow_dissector.c | 55 ++++++++++++++++++++++++++++++++----
2 files changed, 60 insertions(+), 6 deletions(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index a4c6057c7097..8ff40c7c3f1c 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h@@ -261,6 +261,16 @@ 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 + */ +struct flow_dissector_key_pppoe { + u16 session_id; + __be16 ppp_proto; +}; + enum flow_dissector_key_id { FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */ FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
@@ -291,6 +301,7 @@ 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, };
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 6aee04f75e3e..42393af477a2 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c@@ -895,6 +895,39 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, return result == BPF_OK; } +/** + * is_ppp_proto_supported - checks if inner PPP protocol should be dissected + * @proto: protocol type (PPP proto field) + */ +static bool is_ppp_proto_supported(__be16 proto) +{ + switch (proto) { + case htons(PPP_AT): + case htons(PPP_IPX): + case htons(PPP_VJC_COMP): + case htons(PPP_VJC_UNCOMP): + case htons(PPP_MP): + case htons(PPP_COMPFRAG): + case htons(PPP_COMP): + case htons(PPP_MPLS_UC): + case htons(PPP_MPLS_MC): + case htons(PPP_IPCP): + case htons(PPP_ATCP): + case htons(PPP_IPXCP): + case htons(PPP_IPV6CP): + case htons(PPP_CCPFRAG): + case htons(PPP_MPLSCP): + case htons(PPP_LCP): + case htons(PPP_PAP): + case htons(PPP_LQR): + case htons(PPP_CHAP): + case htons(PPP_CBCP): + return true; + default: + return false; + } +} + /** * __skb_flow_dissect - extract the flow_keys struct and return it * @net: associated network namespace, derived from @skb if NULL
@@ -1221,19 +1254,29 @@ bool __skb_flow_dissect(const struct net *net, } nhoff += PPPOE_SES_HLEN; - switch (hdr->proto) { - case htons(PPP_IP): + if (hdr->proto == htons(PPP_IP)) { proto = htons(ETH_P_IP); fdret = FLOW_DISSECT_RET_PROTO_AGAIN; - break; - case htons(PPP_IPV6): + } else if (hdr->proto == htons(PPP_IPV6)) { proto = htons(ETH_P_IPV6); fdret = FLOW_DISSECT_RET_PROTO_AGAIN; - break; - default: + } else if (is_ppp_proto_supported(hdr->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 = ntohs(hdr->hdr.sid); + key_pppoe->ppp_proto = hdr->proto; + } break; } case htons(ETH_P_TIPC): {
--
2.35.1