Commit c02fdc0e authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

[DCCP]: Make feature negotiation more readable 



This patch replaces cryptic feature negotiation messages of type

Oct 31 15:42:20 kernel: dccp_feat_change: feat change type=32 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=34 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=32 feat=5

into ones of type:

Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeR(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(Ack Ratio (5), 2)

Also,
	* completed the feature number list wrt RFC 4340 sec. 6.4
	* annotating which ones have been implemented so far
	* implemented rudimentary sanity checking in feat.c (FIXMEs)
	* some minor fixes

Commiter note: uninlined dccp_feat_name and dccp_feat_typename, for
               consistency with dccp_{state,packet}_name, that, BTW,
               should be compiled only if CONFIG_IP_DCCP_DEBUG is
               selected, leaving this to another cset tho. Also
               shortened dccp_feat_negotiation_debug to dccp_feat_debug.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
parent 6a128e05

include/linux/dccp.h

+14 −11
Original line number Diff line number Diff line
@@ -175,15 +175,18 @@ enum { 
	DCCPC_CCID3 = 3,

};



/* DCCP features */

/* DCCP features (RFC 4340 section 6.4) */

 enum {

 	DCCPF_RESERVED = 0,

 	DCCPF_CCID = 1,

	DCCPF_SHORT_SEQNOS = 2,		/* XXX: not yet implemented */

 	DCCPF_SEQUENCE_WINDOW = 3,

	DCCPF_ECN_INCAPABLE = 4,	/* XXX: not yet implemented */

 	DCCPF_ACK_RATIO = 5,

 	DCCPF_SEND_ACK_VECTOR = 6,

 	DCCPF_SEND_NDP_COUNT = 7,

	DCCPF_MIN_CSUM_COVER = 8,

	DCCPF_DATA_CHECKSUM = 9,	/* XXX: not yet implemented */

 	/* 10-127 reserved */

 	DCCPF_MIN_CCID_SPECIFIC = 128,

 	DCCPF_MAX_CCID_SPECIFIC = 255,

net/dccp/feat.c

+89 −27
Original line number Diff line number Diff line
@@ -12,7 +12,6 @@ 


#include <linux/module.h>



#include "dccp.h"

#include "ccid.h"

#include "feat.h"
@@ -23,9 +22,17 @@ int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, 
{

	struct dccp_opt_pend *opt;



	dccp_pr_debug("feat change type=%d feat=%d\n", type, feature);

	dccp_feat_debug(type, feature, *val);



	/* XXX sanity check feat change request */

	if (!dccp_feat_is_valid_type(type)) {

		pr_info("option type %d invalid in negotiation\n", type);

		return 1;

	}

	if (!dccp_feat_is_valid_length(type, feature, len)) {

		pr_info("invalid length %d\n", len);

		return 1;

	}

	/* XXX add further sanity checks */



	/* check if that feature is already being negotiated */

	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
@@ -95,14 +102,14 @@ static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) 
/* XXX taking only u8 vals */

static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)

{

	dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val);

	dccp_feat_debug(type, feat, val);



	switch (feat) {

	case DCCPF_CCID:

		return dccp_feat_update_ccid(sk, type, val);

	default:

		dccp_pr_debug("IMPLEMENT changing [%d] feat %d to %d\n",

			      type, feat, val);

		dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",

			      dccp_feat_typename(type), feat);

		break;

	}

	return 0;
@@ -265,10 +272,10 @@ static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 
	u8 *copy;

	int rc;



	/* NN features must be change L */

	if (type == DCCPO_CHANGE_R) {

		dccp_pr_debug("received CHANGE_R %d for NN feat %d\n",

			      type, feature);

	/* NN features must be Change L (sec. 6.3.2) */

	if (type != DCCPO_CHANGE_L) {

		dccp_pr_debug("received %s for NN feature %d\n",

				dccp_feat_typename(type), feature);

		return -EFAULT;

	}
@@ -299,7 +306,8 @@ static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 
		return rc;

	}



	dccp_pr_debug("Confirming NN feature %d (val=%d)\n", feature, *copy);

	dccp_feat_debug(type, feature, *copy);



	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);



	return 0;
@@ -318,14 +326,19 @@ static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, 
		return;

	}



	opt->dccpop_type = type == DCCPO_CHANGE_L ? DCCPO_CONFIRM_R :

						    DCCPO_CONFIRM_L;

	switch (type) {

	case DCCPO_CHANGE_L: opt->dccpop_type = DCCPO_CONFIRM_R; break;

	case DCCPO_CHANGE_R: opt->dccpop_type = DCCPO_CONFIRM_L; break;

	default: 	     pr_info("invalid type %d\n", type); return;



	}

	opt->dccpop_feat = feature;

	opt->dccpop_val	 = NULL;

	opt->dccpop_len	 = 0;



	/* change feature */

	dccp_pr_debug("Empty confirm feature %d type %d\n", feature, type);

	dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);



	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);

}
@@ -359,7 +372,7 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 
{

	int rc;



	dccp_pr_debug("got feat change type=%d feat=%d\n", type, feature);

	dccp_feat_debug(type, feature, *val);



	/* figure out if it's SP or NN feature */

	switch (feature) {
@@ -375,6 +388,8 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 


	/* XXX implement other features */

	default:

		dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",

			      dccp_feat_typename(type), feature);

		rc = -EFAULT;

		break;

	}
@@ -403,20 +418,27 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, 
	u8 t;

	struct dccp_opt_pend *opt;

	struct dccp_minisock *dmsk = dccp_msk(sk);

	int rc = 1;

	int found = 0;

	int all_confirmed = 1;



	dccp_pr_debug("got feat confirm type=%d feat=%d\n", type, feature);



	/* XXX sanity check type & feat */

	dccp_feat_debug(type, feature, *val);



	/* locate our change request */

	t = type == DCCPO_CONFIRM_L ? DCCPO_CHANGE_R : DCCPO_CHANGE_L;

	switch (type) {

	case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;

	case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;

	default: 	      pr_info("invalid type %d\n", type);

			      return 1;



	}

	/* XXX sanity check feature value */



	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {

		if (!opt->dccpop_conf && opt->dccpop_type == t &&

		    opt->dccpop_feat == feature) {

			/* we found it */

			found = 1;

			dccp_pr_debug("feature %d found\n", opt->dccpop_feat);



			/* XXX do sanity check */



			opt->dccpop_conf = 1;
@@ -425,9 +447,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, 
			dccp_feat_update(sk, opt->dccpop_type,

					 opt->dccpop_feat, *val);



			dccp_pr_debug("feat %d type %d confirmed %d\n",

				      feature, type, *val);

			rc = 0;

			/* XXX check the return value of dccp_feat_update */

			break;

		}
@@ -446,9 +466,9 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, 
		inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);

	}



	if (rc)

		dccp_pr_debug("feat %d type %d never requested\n",

			      feature, type);

	if (!found)

		dccp_pr_debug("%s(%d, ...) never requested\n",

			      dccp_feat_typename(type), feature);

	return 0;

}
@@ -583,3 +603,45 @@ out: 
}



EXPORT_SYMBOL_GPL(dccp_feat_init);



#ifdef CONFIG_IP_DCCP_DEBUG

const char *dccp_feat_typename(const u8 type)

{

	switch(type) {

	case DCCPO_CHANGE_L:  return("ChangeL");

	case DCCPO_CONFIRM_L: return("ConfirmL");

	case DCCPO_CHANGE_R:  return("ChangeR");

	case DCCPO_CONFIRM_R: return("ConfirmR");

	/* the following case must not appear in feature negotation  */

	default: 	      dccp_pr_debug("unknown type %d [BUG!]\n", type);

	}

	return NULL;

}



EXPORT_SYMBOL_GPL(dccp_feat_typename);



const char *dccp_feat_name(const u8 feat)

{

	static const char *feature_names[] = {

		[DCCPF_RESERVED]	= "Reserved",

		[DCCPF_CCID]		= "CCID",

		[DCCPF_SHORT_SEQNOS]	= "Allow Short Seqnos",

		[DCCPF_SEQUENCE_WINDOW]	= "Sequence Window",

		[DCCPF_ECN_INCAPABLE]	= "ECN Incapable",

		[DCCPF_ACK_RATIO]	= "Ack Ratio",

		[DCCPF_SEND_ACK_VECTOR]	= "Send ACK Vector",

		[DCCPF_SEND_NDP_COUNT]	= "Send NDP Count",

		[DCCPF_MIN_CSUM_COVER]	= "Min. Csum Coverage",

		[DCCPF_DATA_CHECKSUM]	= "Send Data Checksum",

	};

	if (feat >= DCCPF_MIN_CCID_SPECIFIC)

		return "CCID-specific";



	if (dccp_feat_is_reserved(feat))

		return feature_names[DCCPF_RESERVED];



	return feature_names[feat];

}



EXPORT_SYMBOL_GPL(dccp_feat_name);

#endif /* CONFIG_IP_DCCP_DEBUG */

net/dccp/feat.h

+39 −2
Original line number Diff line number Diff line
@@ -12,9 +12,46 @@ 
 */



#include <linux/types.h>

#include "dccp.h"



struct sock;

struct dccp_minisock;

static inline int dccp_feat_is_valid_length(u8 type, u8 feature, u8 len)

{

	/* sec. 6.1: Confirm has at least length 3,

	 * sec. 6.2: Change  has at least length 4 */

	if (len < 3)

		return 1;

	if (len < 4  && (type == DCCPO_CHANGE_L || type == DCCPO_CHANGE_R))

		return 1;

	/* XXX: add per-feature length validation (sec. 6.6.8) */

	return 0;

}



static inline int dccp_feat_is_reserved(const u8 feat)

{

	return (feat > DCCPF_DATA_CHECKSUM &&

		feat < DCCPF_MIN_CCID_SPECIFIC) ||

	        feat == DCCPF_RESERVED;

}



/* feature negotiation knows only these four option types (RFC 4340, sec. 6) */

static inline int dccp_feat_is_valid_type(const u8 optnum)

{

	return optnum >= DCCPO_CHANGE_L && optnum <= DCCPO_CONFIRM_R;



}



#ifdef CONFIG_IP_DCCP_DEBUG

extern const char *dccp_feat_typename(const u8 type);

extern const char *dccp_feat_name(const u8 feat);



static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)

{

	dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type),

					   dccp_feat_name(feat), feat, val);

}

#else

#define dccp_feat_debug(type, feat, val)

#endif /* CONFIG_IP_DCCP_DEBUG */



extern int  dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,

			     u8 *val, u8 len, gfp_t gfp);

net/dccp/options.c

+3 −1
Original line number Diff line number Diff line
@@ -465,8 +465,10 @@ static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat, 


	if (len)

		memcpy(to, val, len);

	dccp_pr_debug("option %d feat %d len %d\n", type, feat, len);



	dccp_pr_debug("%s(%s (%d), ...), length %d\n",

		      dccp_feat_typename(type),

		      dccp_feat_name(feat), feat, len);

	return 0;

}

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