[NET] Generalise TCP's struct open_request minisock infrastructure

Kept this first changeset minimal, without changing existing names to
ease peer review.

Basicaly tcp_openreq_alloc now receives the or_calltable, that in turn
has two new members:

->slab, that replaces tcp_openreq_cachep
->obj_size, to inform the size of the openreq descendant for
  a specific protocol

The protocol specific fields in struct open_request were moved to a
class hierarchy, with the things that are common to all connection
oriented PF_INET protocols in struct inet_request_sock, the TCP ones
in tcp_request_sock, that is an inet_request_sock, that is an
open_request.

I.e. this uses the same approach used for the struct sock class
hierarchy, with sk_prot indicating if the protocol wants to use the
open_request infrastructure by filling in sk_prot->rsk_prot with an
or_calltable.

Results? Performance is improved and TCP v4 now uses only 64 bytes per
open request minisock, down from 96 without this patch :-)

Next changeset will rename some of the structs, fields and functions
mentioned above, struct or_calltable is way unclear, better name it
struct request_sock_ops, s/struct open_request/struct request_sock/g,
etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 51 insertions, 45 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0f69e800a0ad..9199ad2fde0d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -407,11 +407,13 @@ static struct open_request *tcp_v6_search_req(struct tcp_sock *tp,
         for (prev = &lopt->syn_table[tcp_v6_synq_hash(raddr, rport, lopt->hash_rnd)];
              (req = *prev) != NULL;
              prev = &req->dl_next) {
-                if (req->rmt_port == rport &&
+                const struct tcp6_request_sock *treq = tcp6_rsk(req);
+
+                if (inet_rsk(req)->rmt_port == rport &&
                     req->class->family == AF_INET6 &&
-                    ipv6_addr_equal(&req->af.v6_req.rmt_addr, raddr) &&
-                    ipv6_addr_equal(&req->af.v6_req.loc_addr, laddr) &&
-                    (!req->af.v6_req.iif || req->af.v6_req.iif == iif)) {
+                    ipv6_addr_equal(&treq->rmt_addr, raddr) &&
+                    ipv6_addr_equal(&treq->loc_addr, laddr) &&
+                    (!treq->iif || treq->iif == iif)) {
                         BUG_TRAP(req->sk == NULL);
                         *prevp = prev;
                         return req;
@@ -923,7 +925,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                  */
                 BUG_TRAP(req->sk == NULL);
 
-                if (seq != req->snt_isn) {
+                if (seq != tcp_rsk(req)->snt_isn) {
                         NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
                         goto out;
                 }
@@ -960,6 +962,7 @@ out:
 static int tcp_v6_send_synack(struct sock *sk, struct open_request *req,
                               struct dst_entry *dst)
 {
+        struct tcp6_request_sock *treq = tcp6_rsk(req);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct sk_buff * skb;
         struct ipv6_txoptions *opt = NULL;
@@ -969,19 +972,19 @@ static int tcp_v6_send_synack(struct sock *sk, struct open_request *req,
 
         memset(&fl, 0, sizeof(fl));
         fl.proto = IPPROTO_TCP;
-        ipv6_addr_copy(&fl.fl6_dst, &req->af.v6_req.rmt_addr);
-        ipv6_addr_copy(&fl.fl6_src, &req->af.v6_req.loc_addr);
+        ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
+        ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
         fl.fl6_flowlabel = 0;
-        fl.oif = req->af.v6_req.iif;
-        fl.fl_ip_dport = req->rmt_port;
+        fl.oif = treq->iif;
+        fl.fl_ip_dport = inet_rsk(req)->rmt_port;
         fl.fl_ip_sport = inet_sk(sk)->sport;
 
         if (dst == NULL) {
                 opt = np->opt;
                 if (opt == NULL &&
                     np->rxopt.bits.srcrt == 2 &&
-                    req->af.v6_req.pktopts) {
-                        struct sk_buff *pktopts = req->af.v6_req.pktopts;
+                    treq->pktopts) {
+                        struct sk_buff *pktopts = treq->pktopts;
                         struct inet6_skb_parm *rxopt = IP6CB(pktopts);
                         if (rxopt->srcrt)
                                 opt = ipv6_invert_rthdr(sk, (struct ipv6_rt_hdr*)(pktopts->nh.raw + rxopt->srcrt));
@@ -1008,10 +1011,10 @@ static int tcp_v6_send_synack(struct sock *sk, struct open_request *req,
                 struct tcphdr *th = skb->h.th;
 
                 th->check = tcp_v6_check(th, skb->len,
-                                         &req->af.v6_req.loc_addr, &req->af.v6_req.rmt_addr,
+                                         &treq->loc_addr, &treq->rmt_addr,
                                          csum_partial((char *)th, skb->len, skb->csum));
 
-                ipv6_addr_copy(&fl.fl6_dst, &req->af.v6_req.rmt_addr);
+                ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
                 err = ip6_xmit(sk, skb, &fl, opt, 0);
                 if (err == NET_XMIT_CN)
                         err = 0;
@@ -1026,12 +1029,13 @@ done:
 
 static void tcp_v6_or_free(struct open_request *req)
 {
-        if (req->af.v6_req.pktopts)
-                kfree_skb(req->af.v6_req.pktopts);
+        if (tcp6_rsk(req)->pktopts)
+                kfree_skb(tcp6_rsk(req)->pktopts);
 }
 
 static struct or_calltable or_ipv6 = {
         .family         =       AF_INET6,
+        .obj_size       =       sizeof(struct tcp6_request_sock),
         .rtx_syn_ack    =       tcp_v6_send_synack,
         .send_ack       =       tcp_v6_or_send_ack,
         .destructor     =       tcp_v6_or_free,
@@ -1221,7 +1225,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
 static void tcp_v6_or_send_ack(struct sk_buff *skb, struct open_request *req)
 {
-        tcp_v6_send_ack(skb, req->snt_isn+1, req->rcv_isn+1, req->rcv_wnd, req->ts_recent);
+        tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent);
 }
 
 
@@ -1264,7 +1268,7 @@ static void tcp_v6_synq_add(struct sock *sk, struct open_request *req)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct tcp_listen_opt *lopt = tp->listen_opt;
-        u32 h = tcp_v6_synq_hash(&req->af.v6_req.rmt_addr, req->rmt_port, lopt->hash_rnd);
+        u32 h = tcp_v6_synq_hash(&tcp6_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, lopt->hash_rnd);
 
         req->sk = NULL;
         req->expires = jiffies + TCP_TIMEOUT_INIT;
@@ -1284,6 +1288,7 @@ static void tcp_v6_synq_add(struct sock *sk, struct open_request *req)
  */
 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 {
+        struct tcp6_request_sock *treq;
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct tcp_options_received tmp_opt;
         struct tcp_sock *tp = tcp_sk(sk);
@@ -1308,7 +1313,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
         if (sk_acceptq_is_full(sk) && tcp_synq_young(sk) > 1)
                 goto drop;
 
-        req = tcp_openreq_alloc();
+        req = tcp_openreq_alloc(&or_ipv6);
         if (req == NULL)
                 goto drop;
 
@@ -1321,28 +1326,28 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
         tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
         tcp_openreq_init(req, &tmp_opt, skb);
 
-        req->class = &or_ipv6;
-        ipv6_addr_copy(&req->af.v6_req.rmt_addr, &skb->nh.ipv6h->saddr);
-        ipv6_addr_copy(&req->af.v6_req.loc_addr, &skb->nh.ipv6h->daddr);
+        treq = tcp6_rsk(req);
+        ipv6_addr_copy(&treq->rmt_addr, &skb->nh.ipv6h->saddr);
+        ipv6_addr_copy(&treq->loc_addr, &skb->nh.ipv6h->daddr);
         TCP_ECN_create_request(req, skb->h.th);
-        req->af.v6_req.pktopts = NULL;
+        treq->pktopts = NULL;
         if (ipv6_opt_accepted(sk, skb) ||
             np->rxopt.bits.rxinfo ||
             np->rxopt.bits.rxhlim) {
                 atomic_inc(&skb->users);
-                req->af.v6_req.pktopts = skb;
+                treq->pktopts = skb;
         }
-        req->af.v6_req.iif = sk->sk_bound_dev_if;
+        treq->iif = sk->sk_bound_dev_if;
 
         /* So that link locals have meaning */
         if (!sk->sk_bound_dev_if &&
-            ipv6_addr_type(&req->af.v6_req.rmt_addr) & IPV6_ADDR_LINKLOCAL)
-                req->af.v6_req.iif = tcp_v6_iif(skb);
+            ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
+                treq->iif = tcp_v6_iif(skb);
 
         if (isn == 0) 
                 isn = tcp_v6_init_sequence(sk,skb);
 
-        req->snt_isn = isn;
+        tcp_rsk(req)->snt_isn = isn;
 
         if (tcp_v6_send_synack(sk, req, NULL))
                 goto drop;
@@ -1363,6 +1368,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
                                           struct open_request *req,
                                           struct dst_entry *dst)
 {
+        struct tcp6_request_sock *treq = tcp6_rsk(req);
         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
         struct tcp6_sock *newtcp6sk;
         struct inet_sock *newinet;
@@ -1426,10 +1432,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
                 goto out_overflow;
 
         if (np->rxopt.bits.srcrt == 2 &&
-            opt == NULL && req->af.v6_req.pktopts) {
-                struct inet6_skb_parm *rxopt = IP6CB(req->af.v6_req.pktopts);
+            opt == NULL && treq->pktopts) {
+                struct inet6_skb_parm *rxopt = IP6CB(treq->pktopts);
                 if (rxopt->srcrt)
-                        opt = ipv6_invert_rthdr(sk, (struct ipv6_rt_hdr*)(req->af.v6_req.pktopts->nh.raw+rxopt->srcrt));
+                        opt = ipv6_invert_rthdr(sk, (struct ipv6_rt_hdr *)(treq->pktopts->nh.raw + rxopt->srcrt));
         }
 
         if (dst == NULL) {
@@ -1438,16 +1444,16 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
                 memset(&fl, 0, sizeof(fl));
                 fl.proto = IPPROTO_TCP;
-                ipv6_addr_copy(&fl.fl6_dst, &req->af.v6_req.rmt_addr);
+                ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
                 if (opt && opt->srcrt) {
                         struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
                         ipv6_addr_copy(&final, &fl.fl6_dst);
                         ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
                         final_p = &final;
                 }
-                ipv6_addr_copy(&fl.fl6_src, &req->af.v6_req.loc_addr);
+                ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
                 fl.oif = sk->sk_bound_dev_if;
-                fl.fl_ip_dport = req->rmt_port;
+                fl.fl_ip_dport = inet_rsk(req)->rmt_port;
                 fl.fl_ip_sport = inet_sk(sk)->sport;
 
                 if (ip6_dst_lookup(sk, &dst, &fl))
@@ -1482,10 +1488,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 
-        ipv6_addr_copy(&newnp->daddr, &req->af.v6_req.rmt_addr);
-        ipv6_addr_copy(&newnp->saddr, &req->af.v6_req.loc_addr);
-        ipv6_addr_copy(&newnp->rcv_saddr, &req->af.v6_req.loc_addr);
-        newsk->sk_bound_dev_if = req->af.v6_req.iif;
+        ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
+        ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
+        ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
+        newsk->sk_bound_dev_if = treq->iif;
 
         /* Now IPv6 options... 
 
@@ -1498,11 +1504,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
         /* Clone pktoptions received with SYN */
         newnp->pktoptions = NULL;
-        if (req->af.v6_req.pktopts) {
-                newnp->pktoptions = skb_clone(req->af.v6_req.pktopts,
-                                              GFP_ATOMIC);
-                kfree_skb(req->af.v6_req.pktopts);
-                req->af.v6_req.pktopts = NULL;
+        if (treq->pktopts != NULL) {
+                newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
+                kfree_skb(treq->pktopts);
+                treq->pktopts = NULL;
                 if (newnp->pktoptions)
                         skb_set_owner_r(newnp->pktoptions, newsk);
         }
@@ -2058,8 +2063,8 @@ static void get_openreq6(struct seq_file *seq,
         if (ttd < 0)
                 ttd = 0;
 
-        src = &req->af.v6_req.loc_addr;
-        dest = &req->af.v6_req.rmt_addr;
+        src = &tcp6_rsk(req)->loc_addr;
+        dest = &tcp6_rsk(req)->rmt_addr;
         seq_printf(seq,
                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
@@ -2069,7 +2074,7 @@ static void get_openreq6(struct seq_file *seq,
                    ntohs(inet_sk(sk)->sport),
                    dest->s6_addr32[0], dest->s6_addr32[1],
                    dest->s6_addr32[2], dest->s6_addr32[3],
-                   ntohs(req->rmt_port),
+                   ntohs(inet_rsk(req)->rmt_port),
                    TCP_SYN_RECV,
                    0,0, /* could print option size, but that is af dependent. */
                    1,   /* timers active (only the expire timer) */  
@@ -2239,6 +2244,7 @@ struct proto tcpv6_prot = {
         .sysctl_rmem            = sysctl_tcp_rmem,
         .max_header             = MAX_TCP_HEADER,
         .obj_size               = sizeof(struct tcp6_sock),
+        .rsk_prot               = &or_ipv6,
 };
 
 static struct inet6_protocol tcpv6_protocol = {