From: Tom Herbert <tom@quantonium.net>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, alex.popov@linux.com,
hannes@stressinduktion.org, Tom Herbert <tom@quantonium.net>
Subject: [PATCH net-next 1/2] flow_dissector: Cleanup control flow
Date: Thu, 31 Aug 2017 15:22:38 -0700 [thread overview]
Message-ID: <20170831222239.21509-2-tom@quantonium.net> (raw)
In-Reply-To: <20170831222239.21509-1-tom@quantonium.net>
__skb_flow_dissect is riddled with gotos that make discerning the flow,
debugging, and extending the capability difficult. This patch
reorganizes things so that we only perform goto's after the two main
switch statements (no gotos within the cases now). It also eliminates
several goto labels so that there are only two labels that can be target
for goto.
Reported-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
---
include/net/flow_dissector.h | 9 ++
net/core/flow_dissector.c | 225 ++++++++++++++++++++++++++++---------------
2 files changed, 156 insertions(+), 78 deletions(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index e2663e900b0a..c358c3ff6acc 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -19,6 +19,15 @@ struct flow_dissector_key_control {
#define FLOW_DIS_FIRST_FRAG BIT(1)
#define FLOW_DIS_ENCAPSULATION BIT(2)
+enum flow_dissect_ret {
+ FLOW_DISSECT_RET_OUT_GOOD,
+ FLOW_DISSECT_RET_OUT_BAD,
+ FLOW_DISSECT_RET_PROTO_AGAIN,
+ FLOW_DISSECT_RET_IPPROTO_AGAIN,
+ FLOW_DISSECT_RET_IPPROTO_AGAIN_EH,
+ FLOW_DISSECT_RET_CONTINUE,
+};
+
/**
* struct flow_dissector_key_basic:
* @thoff: Transport header offset
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index e2eaa1ff948d..5110180a3e96 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -115,12 +115,6 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
}
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
__skb_flow_dissect_mpls(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
@@ -341,7 +335,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
return FLOW_DISSECT_RET_OUT_GOOD;
- return FLOW_DISSECT_RET_OUT_PROTO_AGAIN;
+ return FLOW_DISSECT_RET_PROTO_AGAIN;
}
static void
@@ -431,6 +425,7 @@ 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;
+ enum flow_dissect_ret fdret;
bool skip_vlan = false;
u8 ip_proto = 0;
bool ret;
@@ -482,14 +477,19 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
}
proto_again:
+ fdret = FLOW_DISSECT_RET_CONTINUE;
+
switch (proto) {
case htons(ETH_P_IP): {
const struct iphdr *iph;
struct iphdr _iph;
-ip:
+
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
- if (!iph || iph->ihl < 5)
- goto out_bad;
+ if (!iph || iph->ihl < 5) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
+
nhoff += iph->ihl * 4;
ip_proto = iph->protocol;
@@ -509,19 +509,25 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
key_control->flags |= FLOW_DIS_IS_FRAGMENT;
if (iph->frag_off & htons(IP_OFFSET)) {
- goto out_good;
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
} else {
key_control->flags |= FLOW_DIS_FIRST_FRAG;
- if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
- goto out_good;
+ if (!(flags &
+ FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) {
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
+ }
}
}
__skb_flow_dissect_ipv4(skb, flow_dissector,
target_container, data, iph);
- if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
- goto out_good;
+ if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) {
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
+ }
break;
}
@@ -529,10 +535,11 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
const struct ipv6hdr *iph;
struct ipv6hdr _iph;
-ipv6:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
- if (!iph)
- goto out_bad;
+ if (!iph) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
ip_proto = iph->nexthdr;
nhoff += sizeof(struct ipv6hdr);
@@ -561,15 +568,17 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
target_container);
key_tags->flow_label = ntohl(flow_label);
}
- if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
- goto out_good;
+ if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) {
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
+ }
}
__skb_flow_dissect_ipv6(skb, flow_dissector,
target_container, data, iph);
if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
- goto out_good;
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
break;
}
@@ -585,12 +594,17 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
if (!vlan_tag_present || eth_type_vlan(skb->protocol)) {
vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
data, hlen, &_vlan);
- if (!vlan)
- goto out_bad;
+ if (!vlan) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
+
proto = vlan->h_vlan_encapsulated_proto;
nhoff += sizeof(*vlan);
- if (skip_vlan)
- goto proto_again;
+ if (skip_vlan) {
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
+ }
}
skip_vlan = true;
@@ -613,7 +627,8 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
}
}
- goto proto_again;
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
}
case htons(ETH_P_PPP_SES): {
struct {
@@ -621,18 +636,27 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
__be16 proto;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
- if (!hdr)
- goto out_bad;
+ if (!hdr) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
+
proto = hdr->proto;
nhoff += PPPOE_SES_HLEN;
switch (proto) {
case htons(PPP_IP):
- goto ip;
+ proto = htons(ETH_P_IP);
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
case htons(PPP_IPV6):
- goto ipv6;
+ proto = htons(ETH_P_IPV6);
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
default:
- goto out_bad;
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
}
+ break;
}
case htons(ETH_P_TIPC): {
struct {
@@ -640,8 +664,10 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
__be32 srcnode;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
- if (!hdr)
- goto out_bad;
+ if (!hdr) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
@@ -651,56 +677,63 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
key_addrs->tipcaddrs.srcnode = hdr->srcnode;
key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
}
- goto out_good;
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
}
case htons(ETH_P_MPLS_UC):
case htons(ETH_P_MPLS_MC):
-mpls:
- switch (__skb_flow_dissect_mpls(skb, flow_dissector,
+ fdret = __skb_flow_dissect_mpls(skb, flow_dissector,
target_container, data,
- nhoff, hlen)) {
- case FLOW_DISSECT_RET_OUT_GOOD:
- goto out_good;
- case FLOW_DISSECT_RET_OUT_BAD:
- default:
- goto out_bad;
- }
+ nhoff, hlen);
+ break;
case htons(ETH_P_FCOE):
- if ((hlen - nhoff) < FCOE_HEADER_LEN)
- goto out_bad;
+ if ((hlen - nhoff) < FCOE_HEADER_LEN) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
nhoff += FCOE_HEADER_LEN;
- goto out_good;
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
case htons(ETH_P_ARP):
case htons(ETH_P_RARP):
- switch (__skb_flow_dissect_arp(skb, flow_dissector,
+ fdret = __skb_flow_dissect_arp(skb, flow_dissector,
target_container, data,
- nhoff, hlen)) {
- case FLOW_DISSECT_RET_OUT_GOOD:
- goto out_good;
- case FLOW_DISSECT_RET_OUT_BAD:
- default:
- goto out_bad;
- }
+ nhoff, hlen);
+ break;
+
+ default:
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
+
+ /* Process result of proto processing */
+ switch (fdret) {
+ case FLOW_DISSECT_RET_OUT_GOOD:
+ goto out_good;
+ case FLOW_DISSECT_RET_PROTO_AGAIN:
+ goto proto_again;
+ case FLOW_DISSECT_RET_CONTINUE:
+ case FLOW_DISSECT_RET_IPPROTO_AGAIN:
+ case FLOW_DISSECT_RET_IPPROTO_AGAIN_EH:
+ break;
+ case FLOW_DISSECT_RET_OUT_BAD:
default:
goto out_bad;
}
ip_proto_again:
+ fdret = FLOW_DISSECT_RET_CONTINUE;
+
switch (ip_proto) {
case IPPROTO_GRE:
- switch (__skb_flow_dissect_gre(skb, key_control, flow_dissector,
+ fdret = __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;
- case FLOW_DISSECT_RET_OUT_BAD:
- goto out_bad;
- case FLOW_DISSECT_RET_OUT_PROTO_AGAIN:
- goto proto_again;
- }
+ &proto, &nhoff, &hlen, flags);
+ break;
+
case NEXTHDR_HOP:
case NEXTHDR_ROUTING:
case NEXTHDR_DEST: {
@@ -711,13 +744,16 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
data, hlen, &_opthdr);
- if (!opthdr)
- goto out_bad;
+ if (!opthdr) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
ip_proto = opthdr[0];
nhoff += (opthdr[1] + 1) << 3;
- goto ip_proto_again;
+ fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN_EH;
+ break;
}
case NEXTHDR_FRAGMENT: {
struct frag_hdr _fh, *fh;
@@ -728,8 +764,10 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
data, hlen, &_fh);
- if (!fh)
- goto out_bad;
+ if (!fh) {
+ fdret = FLOW_DISSECT_RET_OUT_BAD;
+ break;
+ }
key_control->flags |= FLOW_DIS_IS_FRAGMENT;
@@ -738,34 +776,50 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
if (!(fh->frag_off & htons(IP6_OFFSET))) {
key_control->flags |= FLOW_DIS_FIRST_FRAG;
- if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)
- goto ip_proto_again;
+ if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {
+ fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN_EH;
+ break;
+ }
}
- goto out_good;
+
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
}
case IPPROTO_IPIP:
proto = htons(ETH_P_IP);
key_control->flags |= FLOW_DIS_ENCAPSULATION;
- if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
- goto out_good;
+ if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
+ }
+
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
- goto ip;
case IPPROTO_IPV6:
proto = htons(ETH_P_IPV6);
key_control->flags |= FLOW_DIS_ENCAPSULATION;
- if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
- goto out_good;
+ if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
+ fdret = FLOW_DISSECT_RET_OUT_GOOD;
+ break;
+ }
+
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
+
- goto ipv6;
case IPPROTO_MPLS:
proto = htons(ETH_P_MPLS_UC);
- goto mpls;
+ fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
+ break;
+
case IPPROTO_TCP:
__skb_flow_dissect_tcp(skb, flow_dissector, target_container,
data, nhoff, hlen);
break;
+
default:
break;
}
@@ -787,6 +841,21 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
}
+ /* Process result of IP proto processing */
+ switch (fdret) {
+ case FLOW_DISSECT_RET_PROTO_AGAIN:
+ goto proto_again;
+ case FLOW_DISSECT_RET_IPPROTO_AGAIN:
+ case FLOW_DISSECT_RET_IPPROTO_AGAIN_EH:
+ goto ip_proto_again;
+ case FLOW_DISSECT_RET_OUT_GOOD:
+ case FLOW_DISSECT_RET_CONTINUE:
+ break;
+ case FLOW_DISSECT_RET_OUT_BAD:
+ default:
+ goto out_bad;
+ }
+
out_good:
ret = true;
--
2.11.0
next prev parent reply other threads:[~2017-08-31 22:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-31 22:22 [PATCH net-next 0/2] flow_dissector: Flow dissector fixes Tom Herbert
2017-08-31 22:22 ` Tom Herbert [this message]
2017-09-01 12:26 ` [PATCH net-next 1/2] flow_dissector: Cleanup control flow Simon Horman
2017-09-01 12:35 ` Hannes Frederic Sowa
2017-09-01 16:12 ` Tom Herbert
2017-08-31 22:22 ` [PATCH net-next 2/2] flow_dissector: Add limits for encapsulation and EH Tom Herbert
2017-09-01 12:22 ` Simon Horman
2017-09-01 13:32 ` Hannes Frederic Sowa
2017-09-01 15:38 ` Tom Herbert
2017-09-01 16:35 ` Hannes Frederic Sowa
2017-09-01 16:49 ` Tom Herbert
2017-09-01 17:05 ` Hannes Frederic Sowa
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170831222239.21509-2-tom@quantonium.net \
--to=tom@quantonium.net \
--cc=alex.popov@linux.com \
--cc=davem@davemloft.net \
--cc=hannes@stressinduktion.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox