[TCPDIAG]: Implement cheapest way of supporting DCCPDIAG_GETSOCK

With ugly ifdefs, etc, but this actually:

1. keeps the existing ABI, i.e. no need to recompile the iproute2
   utilities if not interested in DCCP.

2. Provides all the tcp_diag functionality in DCCP, with just a
   small patch that makes iproute2 support DCCP.

Of course I'll get this cleaned-up in time, but for now I think its
OK to be this way to quickly get this functionality.

iproute2-ss050808 patch at:

http://vger.kernel.org/~acme/iproute2-ss050808.dccp.patch

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

2 files changed, 63 insertions, 25 deletions

diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index f6da9328221e..d3770aed3b15 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -34,6 +34,8 @@ struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
         .port_rover     = 1024 - 1,
 };
 
+EXPORT_SYMBOL_GPL(dccp_hashinfo);
+
 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
 {
         return inet_csk_get_port(&dccp_hashinfo, sk, snum);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 4288ecfec9a7..f5fc84aaa9b4 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -45,11 +45,15 @@ static struct sock *tcpnl;
 #define TCPDIAG_PUT(skb, attrtype, attrlen) \
         RTA_DATA(__RTA_PUT(skb, attrtype, attrlen))
 
+#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
+extern struct inet_hashinfo dccp_hashinfo;
+#endif
+
 static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
-                        int ext, u32 pid, u32 seq, u16 nlmsg_flags)
+                        int ext, u32 pid, u32 seq, u16 nlmsg_flags,
+                        const struct nlmsghdr *unlh)
 {
         const struct inet_sock *inet = inet_sk(sk);
-        struct tcp_sock *tp = tcp_sk(sk);
         const struct inet_connection_sock *icsk = inet_csk(sk);
         struct tcpdiagmsg *r;
         struct nlmsghdr  *nlh;
@@ -57,7 +61,7 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
         struct tcpdiag_meminfo  *minfo = NULL;
         unsigned char    *b = skb->tail;
 
-        nlh = NLMSG_PUT(skb, pid, seq, TCPDIAG_GETSOCK, sizeof(*r));
+        nlh = NLMSG_PUT(skb, pid, seq, unlh->nlmsg_type, sizeof(*r));
         nlh->nlmsg_flags = nlmsg_flags;
         r = NLMSG_DATA(nlh);
         if (sk->sk_state != TCP_TIME_WAIT) {
@@ -147,8 +151,20 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
                 r->tcpdiag_expires = 0;
         }
 #undef EXPIRES_IN_MS
-        r->tcpdiag_rqueue = tp->rcv_nxt - tp->copied_seq;
-        r->tcpdiag_wqueue = tp->write_seq - tp->snd_una;
+        /*
+         * Ahem... for now we'll have some knowledge about TCP -acme
+         * But this is just one of two small exceptions, both in this
+         * function, so lets close our eyes for some 15 lines or so... 8)
+         * -acme
+         */
+        if (sk->sk_protocol == IPPROTO_TCP) {
+                const struct tcp_sock *tp = tcp_sk(sk);
+
+                r->tcpdiag_rqueue = tp->rcv_nxt - tp->copied_seq;
+                r->tcpdiag_wqueue = tp->write_seq - tp->snd_una;
+        } else
+                r->tcpdiag_rqueue = r->tcpdiag_wqueue = 0;
+
         r->tcpdiag_uid = sock_i_uid(sk);
         r->tcpdiag_inode = sock_i_ino(sk);
 
@@ -159,8 +175,13 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
                 minfo->tcpdiag_tmem = atomic_read(&sk->sk_wmem_alloc);
         }
 
-        if (info) 
-                tcp_get_info(sk, info);
+        /* Ahem... for now we'll have some knowledge about TCP -acme */
+        if (info) {
+                if (sk->sk_protocol == IPPROTO_TCP) 
+                        tcp_get_info(sk, info);
+                else
+                        memset(info, 0, sizeof(*info));
+        }
 
         if (sk->sk_state < TCP_TIME_WAIT &&
             icsk->icsk_ca_ops && icsk->icsk_ca_ops->get_info)
@@ -194,9 +215,13 @@ static int tcpdiag_get_exact(struct sk_buff *in_skb, const struct nlmsghdr *nlh)
         struct sock *sk;
         struct tcpdiagreq *req = NLMSG_DATA(nlh);
         struct sk_buff *rep;
-
+        struct inet_hashinfo *hashinfo = &tcp_hashinfo;
+#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
+        if (nlh->nlmsg_type == DCCPDIAG_GETSOCK)
+                hashinfo = &dccp_hashinfo;
+#endif
         if (req->tcpdiag_family == AF_INET) {
-                sk = inet_lookup(&tcp_hashinfo, req->id.tcpdiag_dst[0],
+                sk = inet_lookup(hashinfo, req->id.tcpdiag_dst[0],
                                  req->id.tcpdiag_dport, req->id.tcpdiag_src[0],
                                  req->id.tcpdiag_sport, req->id.tcpdiag_if);
         }
@@ -230,7 +255,7 @@ static int tcpdiag_get_exact(struct sk_buff *in_skb, const struct nlmsghdr *nlh)
 
         if (tcpdiag_fill(rep, sk, req->tcpdiag_ext,
                          NETLINK_CB(in_skb).pid,
-                         nlh->nlmsg_seq, 0) <= 0)
+                         nlh->nlmsg_seq, 0, nlh) <= 0)
                 BUG();
 
         err = netlink_unicast(tcpnl, rep, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
@@ -436,12 +461,13 @@ static int tcpdiag_dump_sock(struct sk_buff *skb, struct sock *sk,
         }
 
         return tcpdiag_fill(skb, sk, r->tcpdiag_ext, NETLINK_CB(cb->skb).pid,
-                            cb->nlh->nlmsg_seq, NLM_F_MULTI);
+                            cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
 }
 
 static int tcpdiag_fill_req(struct sk_buff *skb, struct sock *sk,
                             struct request_sock *req,
-                            u32 pid, u32 seq)
+                            u32 pid, u32 seq,
+                            const struct nlmsghdr *unlh)
 {
         const struct inet_request_sock *ireq = inet_rsk(req);
         struct inet_sock *inet = inet_sk(sk);
@@ -450,7 +476,7 @@ static int tcpdiag_fill_req(struct sk_buff *skb, struct sock *sk,
         struct nlmsghdr *nlh;
         long tmo;
 
-        nlh = NLMSG_PUT(skb, pid, seq, TCPDIAG_GETSOCK, sizeof(*r));
+        nlh = NLMSG_PUT(skb, pid, seq, unlh->nlmsg_type, sizeof(*r));
         nlh->nlmsg_flags = NLM_F_MULTI;
         r = NLMSG_DATA(nlh);
 
@@ -526,7 +552,7 @@ static int tcpdiag_dump_reqs(struct sk_buff *skb, struct sock *sk,
                 entry.userlocks = sk->sk_userlocks;
         }
 
-        for (j = s_j; j < TCP_SYNQ_HSIZE; j++) {
+        for (j = s_j; j < lopt->nr_table_entries; j++) {
                 struct request_sock *req, *head = lopt->syn_table[j];
 
                 reqnum = 0;
@@ -561,7 +587,7 @@ static int tcpdiag_dump_reqs(struct sk_buff *skb, struct sock *sk,
 
                         err = tcpdiag_fill_req(skb, sk, req,
                                                NETLINK_CB(cb->skb).pid,
-                                               cb->nlh->nlmsg_seq);
+                                               cb->nlh->nlmsg_seq, cb->nlh);
                         if (err < 0) {
                                 cb->args[3] = j + 1;
                                 cb->args[4] = reqnum;
@@ -583,20 +609,26 @@ static int tcpdiag_dump(struct sk_buff *skb, struct netlink_callback *cb)
         int i, num;
         int s_i, s_num;
         struct tcpdiagreq *r = NLMSG_DATA(cb->nlh);
+        struct inet_hashinfo *hashinfo;
 
         s_i = cb->args[1];
         s_num = num = cb->args[2];
-
+                hashinfo = &tcp_hashinfo;
+#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
+        if (cb->nlh->nlmsg_type == DCCPDIAG_GETSOCK)
+                hashinfo = &dccp_hashinfo;
+#endif
         if (cb->args[0] == 0) {
                 if (!(r->tcpdiag_states&(TCPF_LISTEN|TCPF_SYN_RECV)))
                         goto skip_listen_ht;
-                inet_listen_lock(&tcp_hashinfo);
+
+                inet_listen_lock(hashinfo);
                 for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
                         struct sock *sk;
                         struct hlist_node *node;
 
                         num = 0;
-                        sk_for_each(sk, node, &tcp_hashinfo.listening_hash[i]) {
+                        sk_for_each(sk, node, &hashinfo->listening_hash[i]) {
                                 struct inet_sock *inet = inet_sk(sk);
 
                                 if (num < s_num) {
@@ -614,7 +646,7 @@ static int tcpdiag_dump(struct sk_buff *skb, struct netlink_callback *cb)
                                         goto syn_recv;
 
                                 if (tcpdiag_dump_sock(skb, sk, cb) < 0) {
-                                        inet_listen_unlock(&tcp_hashinfo);
+                                        inet_listen_unlock(hashinfo);
                                         goto done;
                                 }
 
@@ -623,7 +655,7 @@ syn_recv:
                                         goto next_listen;
 
                                 if (tcpdiag_dump_reqs(skb, sk, cb) < 0) {
-                                        inet_listen_unlock(&tcp_hashinfo);
+                                        inet_listen_unlock(hashinfo);
                                         goto done;
                                 }
 
@@ -637,7 +669,7 @@ next_listen:
                         cb->args[3] = 0;
                         cb->args[4] = 0;
                 }
-                inet_listen_unlock(&tcp_hashinfo);
+                inet_listen_unlock(hashinfo);
 skip_listen_ht:
                 cb->args[0] = 1;
                 s_i = num = s_num = 0;
@@ -646,8 +678,8 @@ skip_listen_ht:
         if (!(r->tcpdiag_states&~(TCPF_LISTEN|TCPF_SYN_RECV)))
                 return skb->len;
 
-        for (i = s_i; i < tcp_hashinfo.ehash_size; i++) {
-                struct inet_ehash_bucket *head = &tcp_hashinfo.ehash[i];
+        for (i = s_i; i < hashinfo->ehash_size; i++) {
+                struct inet_ehash_bucket *head = &hashinfo->ehash[i];
                 struct sock *sk;
                 struct hlist_node *node;
 
@@ -679,7 +711,7 @@ next_normal:
 
                 if (r->tcpdiag_states&TCPF_TIME_WAIT) {
                         sk_for_each(sk, node,
-                                    &tcp_hashinfo.ehash[i + tcp_hashinfo.ehash_size].chain) {
+                                    &hashinfo->ehash[i + hashinfo->ehash_size].chain) {
                                 struct inet_sock *inet = inet_sk(sk);
 
                                 if (num < s_num)
@@ -719,7 +751,11 @@ tcpdiag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
         if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
                 return 0;
 
-        if (nlh->nlmsg_type != TCPDIAG_GETSOCK)
+        if (nlh->nlmsg_type != TCPDIAG_GETSOCK
+#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
+            && nlh->nlmsg_type != DCCPDIAG_GETSOCK
+#endif
+           )
                 goto err_inval;
 
         if (NLMSG_LENGTH(sizeof(struct tcpdiagreq)) > skb->len)