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authorEric Dumazet <edumazet@google.com>2021-08-03 18:31:05 +0300
committerDavid S. Miller <davem@davemloft.net>2021-08-04 12:34:40 +0300
commit51b8f812e5b327b343232685ea7969e02348d5dd (patch)
tree22d74eb301744d65ab93520fad735c4b3617df26 /net/ipv6
parentd851798584ffd497b6cf0ae68f9ba75afced0ec3 (diff)
downloadlinux-51b8f812e5b327b343232685ea7969e02348d5dd.tar.xz
ipv6: exthdrs: get rid of indirect calls in ip6_parse_tlv()
As presented last month in our "BIG TCP" talk at netdev 0x15, we plan using IPv6 jumbograms. One of the minor problem we talked about is the fact that ip6_parse_tlv() is currently using tables to list known tlvs, thus using potentially expensive indirect calls. While we could mitigate this cost using macros from indirect_call_wrapper.h, we also can get rid of the tables and let the compiler emit optimized code. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Justin Iurman <justin.iurman@uliege.be> Cc: Coco Li <lixiaoyan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/exthdrs.c105
1 files changed, 46 insertions, 59 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index d897faa4e9e6..3a871a09f962 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -55,19 +55,6 @@
#include <linux/uaccess.h>
-/*
- * Parsing tlv encoded headers.
- *
- * Parsing function "func" returns true, if parsing succeed
- * and false, if it failed.
- * It MUST NOT touch skb->h.
- */
-
-struct tlvtype_proc {
- int type;
- bool (*func)(struct sk_buff *skb, int offset);
-};
-
/*********************
Generic functions
*********************/
@@ -112,16 +99,23 @@ drop:
return false;
}
+static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
+#endif
+
/* Parse tlv encoded option header (hop-by-hop or destination) */
-static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
+static bool ip6_parse_tlv(bool hopbyhop,
struct sk_buff *skb,
int max_count)
{
int len = (skb_transport_header(skb)[1] + 1) << 3;
const unsigned char *nh = skb_network_header(skb);
int off = skb_network_header_len(skb);
- const struct tlvtype_proc *curr;
bool disallow_unknowns = false;
int tlv_count = 0;
int padlen = 0;
@@ -176,20 +170,45 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
if (tlv_count > max_count)
goto bad;
- for (curr = procs; curr->type >= 0; curr++) {
- if (curr->type == nh[off]) {
- /* type specific length/alignment
- checks will be performed in the
- func(). */
- if (curr->func(skb, off) == false)
+ if (hopbyhop) {
+ switch (nh[off]) {
+ case IPV6_TLV_ROUTERALERT:
+ if (!ipv6_hop_ra(skb, off))
+ return false;
+ break;
+ case IPV6_TLV_IOAM:
+ if (!ipv6_hop_ioam(skb, off))
+ return false;
+ break;
+ case IPV6_TLV_JUMBO:
+ if (!ipv6_hop_jumbo(skb, off))
+ return false;
+ break;
+ case IPV6_TLV_CALIPSO:
+ if (!ipv6_hop_calipso(skb, off))
+ return false;
+ break;
+ default:
+ if (!ip6_tlvopt_unknown(skb, off,
+ disallow_unknowns))
+ return false;
+ break;
+ }
+ } else {
+ switch (nh[off]) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ case IPV6_TLV_HAO:
+ if (!ipv6_dest_hao(skb, off))
+ return false;
+ break;
+#endif
+ default:
+ if (!ip6_tlvopt_unknown(skb, off,
+ disallow_unknowns))
return false;
break;
}
}
- if (curr->type < 0 &&
- !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
- return false;
-
padlen = 0;
}
off += optlen;
@@ -267,16 +286,6 @@ static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
}
#endif
-static const struct tlvtype_proc tlvprocdestopt_lst[] = {
-#if IS_ENABLED(CONFIG_IPV6_MIP6)
- {
- .type = IPV6_TLV_HAO,
- .func = ipv6_dest_hao,
- },
-#endif
- {-1, NULL}
-};
-
static int ipv6_destopt_rcv(struct sk_buff *skb)
{
struct inet6_dev *idev = __in6_dev_get(skb->dev);
@@ -307,8 +316,7 @@ fail_and_free:
dstbuf = opt->dst1;
#endif
- if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
- net->ipv6.sysctl.max_dst_opts_cnt)) {
+ if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
skb->transport_header += extlen;
opt = IP6CB(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
@@ -1051,26 +1059,6 @@ drop:
return false;
}
-static const struct tlvtype_proc tlvprochopopt_lst[] = {
- {
- .type = IPV6_TLV_ROUTERALERT,
- .func = ipv6_hop_ra,
- },
- {
- .type = IPV6_TLV_IOAM,
- .func = ipv6_hop_ioam,
- },
- {
- .type = IPV6_TLV_JUMBO,
- .func = ipv6_hop_jumbo,
- },
- {
- .type = IPV6_TLV_CALIPSO,
- .func = ipv6_hop_calipso,
- },
- { -1, }
-};
-
int ipv6_parse_hopopts(struct sk_buff *skb)
{
struct inet6_skb_parm *opt = IP6CB(skb);
@@ -1096,8 +1084,7 @@ fail_and_free:
goto fail_and_free;
opt->flags |= IP6SKB_HOPBYHOP;
- if (ip6_parse_tlv(tlvprochopopt_lst, skb,
- net->ipv6.sysctl.max_hbh_opts_cnt)) {
+ if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
skb->transport_header += extlen;
opt = IP6CB(skb);
opt->nhoff = sizeof(struct ipv6hdr);