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[DCCP]: Make feature negotiation more readable
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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: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
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Gerrit Renker authored and David S. Miller committed Dec 3, 2006
1 parent 6a128e0 commit c02fdc0
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Showing 4 changed files with 145 additions and 41 deletions.
25 changes: 14 additions & 11 deletions include/linux/dccp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -175,18 +175,21 @@ enum {
DCCPC_CCID3 = 3,
};

/* DCCP features */
enum {
DCCPF_RESERVED = 0,
DCCPF_CCID = 1,
DCCPF_SEQUENCE_WINDOW = 3,
DCCPF_ACK_RATIO = 5,
DCCPF_SEND_ACK_VECTOR = 6,
DCCPF_SEND_NDP_COUNT = 7,
/* 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,
/* 10-127 reserved */
DCCPF_MIN_CCID_SPECIFIC = 128,
DCCPF_MAX_CCID_SPECIFIC = 255,
DCCPF_DATA_CHECKSUM = 9, /* XXX: not yet implemented */
/* 10-127 reserved */
DCCPF_MIN_CCID_SPECIFIC = 128,
DCCPF_MAX_CCID_SPECIFIC = 255,
};

/* this structure is argument to DCCP_SOCKOPT_CHANGE_X */
Expand Down
116 changes: 89 additions & 27 deletions net/dccp/feat.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@

#include <linux/module.h>

#include "dccp.h"
#include "ccid.h"
#include "feat.h"

Expand All @@ -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) {
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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;
Expand All @@ -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);
}

Expand Down Expand Up @@ -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) {
Expand All @@ -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;
}
Expand Down Expand Up @@ -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;
Expand All @@ -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;
}

Expand All @@ -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;
}

Expand Down Expand Up @@ -583,3 +603,45 @@ int dccp_feat_init(struct dccp_minisock *dmsk)
}

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 */
41 changes: 39 additions & 2 deletions net/dccp/feat.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
4 changes: 3 additions & 1 deletion net/dccp/options.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand Down

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