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>
This commit is contained in:
Eric Dumazet
David S. Miller
parent
d851798584
commit
51b8f812e5
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@ -55,19 +55,6 @@
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#include <linux/uaccess.h>
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/*
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* Parsing tlv encoded headers.
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*
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* Parsing function "func" returns true, if parsing succeed
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* and false, if it failed.
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* It MUST NOT touch skb->h.
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*/
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struct tlvtype_proc {
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int type;
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bool (*func)(struct sk_buff *skb, int offset);
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};
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/*********************
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Generic functions
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*********************/
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@ -112,16 +99,23 @@ static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
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return false;
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}
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static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
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static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
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static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
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static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
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#endif
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/* Parse tlv encoded option header (hop-by-hop or destination) */
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static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
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static bool ip6_parse_tlv(bool hopbyhop,
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struct sk_buff *skb,
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int max_count)
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{
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int len = (skb_transport_header(skb)[1] + 1) << 3;
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const unsigned char *nh = skb_network_header(skb);
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int off = skb_network_header_len(skb);
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const struct tlvtype_proc *curr;
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bool disallow_unknowns = false;
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int tlv_count = 0;
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int padlen = 0;
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@ -176,20 +170,45 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
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if (tlv_count > max_count)
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goto bad;
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for (curr = procs; curr->type >= 0; curr++) {
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if (curr->type == nh[off]) {
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/* type specific length/alignment
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checks will be performed in the
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func(). */
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if (curr->func(skb, off) == false)
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if (hopbyhop) {
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switch (nh[off]) {
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case IPV6_TLV_ROUTERALERT:
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if (!ipv6_hop_ra(skb, off))
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return false;
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break;
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case IPV6_TLV_IOAM:
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if (!ipv6_hop_ioam(skb, off))
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return false;
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break;
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case IPV6_TLV_JUMBO:
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if (!ipv6_hop_jumbo(skb, off))
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return false;
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break;
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case IPV6_TLV_CALIPSO:
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if (!ipv6_hop_calipso(skb, off))
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return false;
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break;
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default:
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if (!ip6_tlvopt_unknown(skb, off,
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disallow_unknowns))
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return false;
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break;
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}
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} else {
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switch (nh[off]) {
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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case IPV6_TLV_HAO:
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if (!ipv6_dest_hao(skb, off))
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return false;
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break;
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#endif
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default:
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if (!ip6_tlvopt_unknown(skb, off,
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disallow_unknowns))
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return false;
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break;
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}
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}
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if (curr->type < 0 &&
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!ip6_tlvopt_unknown(skb, off, disallow_unknowns))
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return false;
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padlen = 0;
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}
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off += optlen;
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@ -267,16 +286,6 @@ static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
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}
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#endif
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static const struct tlvtype_proc tlvprocdestopt_lst[] = {
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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{
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.type = IPV6_TLV_HAO,
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.func = ipv6_dest_hao,
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},
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#endif
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{-1, NULL}
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};
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static int ipv6_destopt_rcv(struct sk_buff *skb)
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{
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struct inet6_dev *idev = __in6_dev_get(skb->dev);
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@ -307,8 +316,7 @@ static int ipv6_destopt_rcv(struct sk_buff *skb)
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dstbuf = opt->dst1;
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#endif
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if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
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net->ipv6.sysctl.max_dst_opts_cnt)) {
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if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
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skb->transport_header += extlen;
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opt = IP6CB(skb);
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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@ -1051,26 +1059,6 @@ static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
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return false;
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}
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static const struct tlvtype_proc tlvprochopopt_lst[] = {
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{
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.type = IPV6_TLV_ROUTERALERT,
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.func = ipv6_hop_ra,
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},
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{
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.type = IPV6_TLV_IOAM,
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.func = ipv6_hop_ioam,
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},
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{
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.type = IPV6_TLV_JUMBO,
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.func = ipv6_hop_jumbo,
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},
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{
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.type = IPV6_TLV_CALIPSO,
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.func = ipv6_hop_calipso,
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},
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{ -1, }
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};
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int ipv6_parse_hopopts(struct sk_buff *skb)
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{
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struct inet6_skb_parm *opt = IP6CB(skb);
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@ -1096,8 +1084,7 @@ int ipv6_parse_hopopts(struct sk_buff *skb)
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goto fail_and_free;
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opt->flags |= IP6SKB_HOPBYHOP;
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if (ip6_parse_tlv(tlvprochopopt_lst, skb,
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net->ipv6.sysctl.max_hbh_opts_cnt)) {
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if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
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skb->transport_header += extlen;
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opt = IP6CB(skb);
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opt->nhoff = sizeof(struct ipv6hdr);
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