From 7c92de8eaabfff42f6f57466c12f255cbd718f58 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Mon, 6 Mar 2017 16:39:55 +0100 Subject: [PATCH] flow_dissector: Move GRE dissection into a separate function Make the main flow_dissect function a bit smaller and move the GRE dissection into a separate function. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller --- net/core/flow_dissector.c | 244 +++++++++++++++++++++----------------- 1 file changed, 134 insertions(+), 110 deletions(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 912083576594..5f3ae922fcd1 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -116,6 +116,7 @@ EXPORT_SYMBOL(__skb_flow_get_ports); enum flow_dissect_ret { FLOW_DISSECT_RET_OUT_GOOD, FLOW_DISSECT_RET_OUT_BAD, + FLOW_DISSECT_RET_OUT_PROTO_AGAIN, }; static enum flow_dissect_ret @@ -200,6 +201,128 @@ __skb_flow_dissect_arp(const struct sk_buff *skb, return FLOW_DISSECT_RET_OUT_GOOD; } +static enum flow_dissect_ret +__skb_flow_dissect_gre(const struct sk_buff *skb, + struct flow_dissector_key_control *key_control, + struct flow_dissector *flow_dissector, + void *target_container, void *data, + __be16 *p_proto, int *p_nhoff, int *p_hlen, + unsigned int flags) +{ + struct flow_dissector_key_keyid *key_keyid; + struct gre_base_hdr *hdr, _hdr; + int offset = 0; + u16 gre_ver; + + hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), + data, *p_hlen, &_hdr); + if (!hdr) + return FLOW_DISSECT_RET_OUT_BAD; + + /* Only look inside GRE without routing */ + if (hdr->flags & GRE_ROUTING) + return FLOW_DISSECT_RET_OUT_GOOD; + + /* Only look inside GRE for version 0 and 1 */ + gre_ver = ntohs(hdr->flags & GRE_VERSION); + if (gre_ver > 1) + return FLOW_DISSECT_RET_OUT_GOOD; + + *p_proto = hdr->protocol; + if (gre_ver) { + /* Version1 must be PPTP, and check the flags */ + if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY))) + return FLOW_DISSECT_RET_OUT_GOOD; + } + + offset += sizeof(struct gre_base_hdr); + + if (hdr->flags & GRE_CSUM) + offset += sizeof(((struct gre_full_hdr *) 0)->csum) + + sizeof(((struct gre_full_hdr *) 0)->reserved1); + + if (hdr->flags & GRE_KEY) { + const __be32 *keyid; + __be32 _keyid; + + keyid = __skb_header_pointer(skb, *p_nhoff + offset, + sizeof(_keyid), + data, *p_hlen, &_keyid); + if (!keyid) + return FLOW_DISSECT_RET_OUT_BAD; + + if (dissector_uses_key(flow_dissector, + FLOW_DISSECTOR_KEY_GRE_KEYID)) { + key_keyid = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_GRE_KEYID, + target_container); + if (gre_ver == 0) + key_keyid->keyid = *keyid; + else + key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK; + } + offset += sizeof(((struct gre_full_hdr *) 0)->key); + } + + if (hdr->flags & GRE_SEQ) + offset += sizeof(((struct pptp_gre_header *) 0)->seq); + + if (gre_ver == 0) { + if (*p_proto == htons(ETH_P_TEB)) { + const struct ethhdr *eth; + struct ethhdr _eth; + + eth = __skb_header_pointer(skb, *p_nhoff + offset, + sizeof(_eth), + data, *p_hlen, &_eth); + if (!eth) + return FLOW_DISSECT_RET_OUT_BAD; + *p_proto = eth->h_proto; + offset += sizeof(*eth); + + /* Cap headers that we access via pointers at the + * end of the Ethernet header as our maximum alignment + * at that point is only 2 bytes. + */ + if (NET_IP_ALIGN) + *p_hlen = *p_nhoff + offset; + } + } else { /* version 1, must be PPTP */ + u8 _ppp_hdr[PPP_HDRLEN]; + u8 *ppp_hdr; + + if (hdr->flags & GRE_ACK) + offset += sizeof(((struct pptp_gre_header *) 0)->ack); + + ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset, + sizeof(_ppp_hdr), + data, *p_hlen, _ppp_hdr); + if (!ppp_hdr) + return FLOW_DISSECT_RET_OUT_BAD; + + switch (PPP_PROTOCOL(ppp_hdr)) { + case PPP_IP: + *p_proto = htons(ETH_P_IP); + break; + case PPP_IPV6: + *p_proto = htons(ETH_P_IPV6); + break; + default: + /* Could probably catch some more like MPLS */ + break; + } + + offset += PPP_HDRLEN; + } + + *p_nhoff += offset; + key_control->flags |= FLOW_DIS_ENCAPSULATION; + if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) + return FLOW_DISSECT_RET_OUT_GOOD; + + return FLOW_DISSECT_RET_OUT_PROTO_AGAIN; +} + /** * __skb_flow_dissect - extract the flow_keys struct and return it * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified @@ -229,7 +352,6 @@ bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector_key_icmp *key_icmp; struct flow_dissector_key_tags *key_tags; struct flow_dissector_key_vlan *key_vlan; - struct flow_dissector_key_keyid *key_keyid; bool skip_vlan = false; u8 ip_proto = 0; bool ret; @@ -443,6 +565,7 @@ mpls: case FLOW_DISSECT_RET_OUT_GOOD: goto out_good; case FLOW_DISSECT_RET_OUT_BAD: + default: goto out_bad; } case htons(ETH_P_FCOE): @@ -460,6 +583,7 @@ mpls: case FLOW_DISSECT_RET_OUT_GOOD: goto out_good; case FLOW_DISSECT_RET_OUT_BAD: + default: goto out_bad; } default: @@ -468,117 +592,17 @@ mpls: ip_proto_again: switch (ip_proto) { - case IPPROTO_GRE: { - struct gre_base_hdr *hdr, _hdr; - u16 gre_ver; - int offset = 0; - - hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); - if (!hdr) - goto out_bad; - - /* Only look inside GRE without routing */ - if (hdr->flags & GRE_ROUTING) - goto out_good; - - /* Only look inside GRE for version 0 and 1 */ - gre_ver = ntohs(hdr->flags & GRE_VERSION); - if (gre_ver > 1) + case IPPROTO_GRE: + switch (__skb_flow_dissect_gre(skb, key_control, flow_dissector, + target_container, data, + &proto, &nhoff, &hlen, flags)) { + case FLOW_DISSECT_RET_OUT_GOOD: goto out_good; - - proto = hdr->protocol; - if (gre_ver) { - /* Version1 must be PPTP, and check the flags */ - if (!(proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY))) - goto out_good; - } - - offset += sizeof(struct gre_base_hdr); - - if (hdr->flags & GRE_CSUM) - offset += sizeof(((struct gre_full_hdr *)0)->csum) + - sizeof(((struct gre_full_hdr *)0)->reserved1); - - if (hdr->flags & GRE_KEY) { - const __be32 *keyid; - __be32 _keyid; - - keyid = __skb_header_pointer(skb, nhoff + offset, sizeof(_keyid), - data, hlen, &_keyid); - if (!keyid) - goto out_bad; - - if (dissector_uses_key(flow_dissector, - FLOW_DISSECTOR_KEY_GRE_KEYID)) { - key_keyid = skb_flow_dissector_target(flow_dissector, - FLOW_DISSECTOR_KEY_GRE_KEYID, - target_container); - if (gre_ver == 0) - key_keyid->keyid = *keyid; - else - key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK; - } - offset += sizeof(((struct gre_full_hdr *)0)->key); - } - - if (hdr->flags & GRE_SEQ) - offset += sizeof(((struct pptp_gre_header *)0)->seq); - - if (gre_ver == 0) { - if (proto == htons(ETH_P_TEB)) { - const struct ethhdr *eth; - struct ethhdr _eth; - - eth = __skb_header_pointer(skb, nhoff + offset, - sizeof(_eth), - data, hlen, &_eth); - if (!eth) - goto out_bad; - proto = eth->h_proto; - offset += sizeof(*eth); - - /* Cap headers that we access via pointers at the - * end of the Ethernet header as our maximum alignment - * at that point is only 2 bytes. - */ - if (NET_IP_ALIGN) - hlen = (nhoff + offset); - } - } else { /* version 1, must be PPTP */ - u8 _ppp_hdr[PPP_HDRLEN]; - u8 *ppp_hdr; - - if (hdr->flags & GRE_ACK) - offset += sizeof(((struct pptp_gre_header *)0)->ack); - - ppp_hdr = __skb_header_pointer(skb, nhoff + offset, - sizeof(_ppp_hdr), - data, hlen, _ppp_hdr); - if (!ppp_hdr) - goto out_bad; - - switch (PPP_PROTOCOL(ppp_hdr)) { - case PPP_IP: - proto = htons(ETH_P_IP); - break; - case PPP_IPV6: - proto = htons(ETH_P_IPV6); - break; - default: - /* Could probably catch some more like MPLS */ - break; - } - - offset += PPP_HDRLEN; + case FLOW_DISSECT_RET_OUT_BAD: + goto out_bad; + case FLOW_DISSECT_RET_OUT_PROTO_AGAIN: + goto proto_again; } - - nhoff += offset; - key_control->flags |= FLOW_DIS_ENCAPSULATION; - if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) - goto out_good; - - goto proto_again; - } case NEXTHDR_HOP: case NEXTHDR_ROUTING: case NEXTHDR_DEST: { -- 2.20.1