[DCCP] CCID: Improve CCID infrastructure

1. No need for ->ccid_init nor ->ccid_exit, this is what module_{init,exit}
   does and anynways neither ccid2 nor ccid3 were using it.

2. Rename struct ccid to struct ccid_operations and introduce struct ccid
   with a pointer to ccid_operations and rigth after it the rx or tx
   private state.

3. Remove the pointer to the state of the half connections from struct
   dccp_sock, now its derived thru ccid_priv() from the ccid pointer.

Now we also can implement the setsockopt for changing the CCID easily as
no ccid init routines can affect struct dccp_sock in any way that prevents
other CCIDs from working if a CCID switch operation is asked by apps.

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

4 files changed, 34 insertions, 76 deletions

diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 3328d23c4be7..b40c4569a820 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -52,16 +52,6 @@ static int ccid2_debug;
 
 static const int ccid2_seq_len = 128;
 
-static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
-{
-	return dccp_sk(sk)->dccps_hc_tx_ccid_private;
-}
-
-static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
-{
-	return dccp_sk(sk)->dccps_hc_rx_ccid_private;
-}
-
 #ifdef CCID2_DEBUG
 static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
 {
@@ -707,19 +697,12 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	ccid2_hc_tx_check_sanity(hctx);
 }
 
-static int ccid2_hc_tx_init(struct sock *sk)
+static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
-        struct ccid2_hc_tx_sock *hctx;
+        struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
 	int seqcount = ccid2_seq_len;
 	int i;
 
-        dp->dccps_hc_tx_ccid_private = kzalloc(sizeof(*hctx), gfp_any());
-        if (dp->dccps_hc_tx_ccid_private == NULL)
-                return -ENOMEM;
-
-        hctx = ccid2_hc_tx_sk(sk);
-
 	/* XXX init variables with proper values */
 	hctx->ccid2hctx_cwnd	  = 1;
 	hctx->ccid2hctx_ssthresh  = 10;
@@ -728,11 +711,9 @@ static int ccid2_hc_tx_init(struct sock *sk)
 	/* XXX init ~ to window size... */
 	hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) *
 					 seqcount, gfp_any());
-	if (hctx->ccid2hctx_seqbuf == NULL) {
-		kfree(dp->dccps_hc_tx_ccid_private);
-		dp->dccps_hc_tx_ccid_private = NULL;
+	if (hctx->ccid2hctx_seqbuf == NULL)
 		return -ENOMEM;
-	}
+
 	for (i = 0; i < (seqcount - 1); i++) {
 		hctx->ccid2hctx_seqbuf[i].ccid2s_next =
 					&hctx->ccid2hctx_seqbuf[i + 1];
@@ -763,15 +744,11 @@ static int ccid2_hc_tx_init(struct sock *sk)
 
 static void ccid2_hc_tx_exit(struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
         struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
 
 	ccid2_hc_tx_kill_rto_timer(sk);
-
 	kfree(hctx->ccid2hctx_seqbuf);
-
-	kfree(dp->dccps_hc_tx_ccid_private);
-	dp->dccps_hc_tx_ccid_private = NULL;
+	hctx->ccid2hctx_seqbuf = NULL;
 }
 
 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
@@ -791,33 +768,17 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-static int ccid2_hc_rx_init(struct sock *sk)
-{
-	struct dccp_sock *dp = dccp_sk(sk);
-        dp->dccps_hc_rx_ccid_private = kzalloc(sizeof(struct ccid2_hc_rx_sock),
-					       gfp_any());
-        return dp->dccps_hc_rx_ccid_private == NULL ? -ENOMEM : 0;
-}
-
-static void ccid2_hc_rx_exit(struct sock *sk)
-{
-	struct dccp_sock *dp = dccp_sk(sk);
-
-	kfree(dp->dccps_hc_rx_ccid_private);
-	dp->dccps_hc_rx_ccid_private = NULL;
-}
-
-static struct ccid ccid2 = {
+static struct ccid_operations ccid2 = {
 	.ccid_id		= 2,
 	.ccid_name		= "ccid2",
 	.ccid_owner		= THIS_MODULE,
+	.ccid_hc_tx_obj_size	= sizeof(struct ccid2_hc_tx_sock),
 	.ccid_hc_tx_init	= ccid2_hc_tx_init,
 	.ccid_hc_tx_exit	= ccid2_hc_tx_exit,
 	.ccid_hc_tx_send_packet	= ccid2_hc_tx_send_packet,
 	.ccid_hc_tx_packet_sent	= ccid2_hc_tx_packet_sent,
 	.ccid_hc_tx_packet_recv	= ccid2_hc_tx_packet_recv,
-	.ccid_hc_rx_init	= ccid2_hc_rx_init,
-	.ccid_hc_rx_exit	= ccid2_hc_rx_exit,
+	.ccid_hc_rx_obj_size	= sizeof(struct ccid2_hc_rx_sock),
 	.ccid_hc_rx_packet_recv	= ccid2_hc_rx_packet_recv,
 };
 
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 0b08c90955a9..451a87464fa5 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -20,6 +20,13 @@
 #ifndef _DCCP_CCID2_H_
 #define _DCCP_CCID2_H_
 
+#include <linux/dccp.h>
+#include <linux/timer.h>
+#include <linux/types.h>
+#include "../ccid.h"
+
+struct sock;
+
 struct ccid2_seq {
 	u64			ccid2s_seq;
 	unsigned long		ccid2s_sent;
@@ -66,4 +73,13 @@ struct ccid2_hc_rx_sock {
 	int	ccid2hcrx_data;
 };
 
+static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
+}
+
+static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
+}
 #endif /* _DCCP_CCID2_H_ */
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index f9e16db09bef..0587f52e4af1 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -647,17 +647,10 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
 	return rc;
 }
 
-static int ccid3_hc_tx_init(struct sock *sk)
+static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
-	struct ccid3_hc_tx_sock *hctx;
-
-	dp->dccps_hc_tx_ccid_private = kmalloc(sizeof(*hctx), gfp_any());
-	if (dp->dccps_hc_tx_ccid_private == NULL)
-		return -ENOMEM;
-
-	hctx = ccid3_hc_tx_sk(sk);
-	memset(hctx, 0, sizeof(*hctx));
+	struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
 
 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
@@ -680,7 +673,6 @@ static int ccid3_hc_tx_init(struct sock *sk)
 
 static void ccid3_hc_tx_exit(struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
 
 	BUG_ON(hctx == NULL);
@@ -690,9 +682,6 @@ static void ccid3_hc_tx_exit(struct sock *sk)
 
 	/* Empty packet history */
 	dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
-
-	kfree(dp->dccps_hc_tx_ccid_private);
-	dp->dccps_hc_tx_ccid_private = NULL;
 }
 
 /*
@@ -1039,20 +1028,13 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-static int ccid3_hc_rx_init(struct sock *sk)
+static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
-	struct ccid3_hc_rx_sock *hcrx;
+	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
 
 	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
 
-	dp->dccps_hc_rx_ccid_private = kmalloc(sizeof(*hcrx), gfp_any());
-	if (dp->dccps_hc_rx_ccid_private == NULL)
-		return -ENOMEM;
-
-	hcrx = ccid3_hc_rx_sk(sk);
-	memset(hcrx, 0, sizeof(*hcrx));
-
 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
 		hcrx->ccid3hcrx_s = dp->dccps_packet_size;
@@ -1071,7 +1053,6 @@ static int ccid3_hc_rx_init(struct sock *sk)
 static void ccid3_hc_rx_exit(struct sock *sk)
 {
 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
-	struct dccp_sock *dp = dccp_sk(sk);
 
 	BUG_ON(hcrx == NULL);
 
@@ -1082,9 +1063,6 @@ static void ccid3_hc_rx_exit(struct sock *sk)
 
 	/* Empty loss interval history */
 	dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
-
-	kfree(dp->dccps_hc_rx_ccid_private);
-	dp->dccps_hc_rx_ccid_private = NULL;
 }
 
 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
@@ -1170,10 +1148,11 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
 	return 0;
 }
 
-static struct ccid ccid3 = {
+static struct ccid_operations ccid3 = {
 	.ccid_id		   = 3,
 	.ccid_name		   = "ccid3",
 	.ccid_owner		   = THIS_MODULE,
+	.ccid_hc_tx_obj_size	   = sizeof(struct ccid3_hc_tx_sock),
 	.ccid_hc_tx_init	   = ccid3_hc_tx_init,
 	.ccid_hc_tx_exit	   = ccid3_hc_tx_exit,
 	.ccid_hc_tx_send_packet	   = ccid3_hc_tx_send_packet,
@@ -1181,6 +1160,7 @@ static struct ccid ccid3 = {
 	.ccid_hc_tx_packet_recv	   = ccid3_hc_tx_packet_recv,
 	.ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
 	.ccid_hc_tx_parse_options  = ccid3_hc_tx_parse_options,
+	.ccid_hc_rx_obj_size	   = sizeof(struct ccid3_hc_rx_sock),
 	.ccid_hc_rx_init	   = ccid3_hc_rx_init,
 	.ccid_hc_rx_exit	   = ccid3_hc_rx_exit,
 	.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 0bde4583d091..f18b96d4e5a2 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -41,6 +41,7 @@
 #include <linux/time.h>
 #include <linux/types.h>
 #include <linux/tfrc.h>
+#include "../ccid.h"
 
 #define TFRC_MIN_PACKET_SIZE	   16
 #define TFRC_STD_PACKET_SIZE	  256
@@ -135,12 +136,12 @@ struct ccid3_hc_rx_sock {
 
 static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
 {
-    return dccp_sk(sk)->dccps_hc_tx_ccid_private;
+    return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
 }
 
 static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
 {
-    return dccp_sk(sk)->dccps_hc_rx_ccid_private;
+    return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
 }
 
 #endif /* _DCCP_CCID3_H_ */