linux/net/dccp/feat.c
Gerrit Renker 0971d17ca3 dccp: Insert feature-negotiation options into skb
This patch replaces the earlier insertion routine from options.c, so that
code specific to feature negotiation can remain in feat.c. This is possible
by calling a function already existing in options.c.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-01 23:27:31 -08:00

1209 lines
33 KiB
C

/*
* net/dccp/feat.c
*
* An implementation of the DCCP protocol
* Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* ASSUMPTIONS
* -----------
* o Feature negotiation is coordinated with connection setup (as in TCP), wild
* changes of parameters of an established connection are not supported.
* o All currently known SP features have 1-byte quantities. If in the future
* extensions of RFCs 4340..42 define features with item lengths larger than
* one byte, a feature-specific extension of the code will be required.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include "ccid.h"
#include "feat.h"
#define DCCP_FEAT_SP_NOAGREE (-123)
static const struct {
u8 feat_num; /* DCCPF_xxx */
enum dccp_feat_type rxtx; /* RX or TX */
enum dccp_feat_type reconciliation; /* SP or NN */
u8 default_value; /* as in 6.4 */
/*
* Lookup table for location and type of features (from RFC 4340/4342)
* +--------------------------+----+-----+----+----+---------+-----------+
* | Feature | Location | Reconc. | Initial | Section |
* | | RX | TX | SP | NN | Value | Reference |
* +--------------------------+----+-----+----+----+---------+-----------+
* | DCCPF_CCID | | X | X | | 2 | 10 |
* | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 |
* | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 |
* | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 |
* | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 |
* | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 |
* | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 |
* | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 |
* | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 |
* | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 |
* +--------------------------+----+-----+----+----+---------+-----------+
*/
} dccp_feat_table[] = {
{ DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2 },
{ DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0 },
{ DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
{ DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0 },
{ DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2 },
{ DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
{ DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0 },
{ DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0 },
{ DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0 },
{ DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0 },
};
#define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table)
/**
* dccp_feat_index - Hash function to map feature number into array position
* Returns consecutive array index or -1 if the feature is not understood.
*/
static int dccp_feat_index(u8 feat_num)
{
/* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)
return feat_num - 1;
/*
* Other features: add cases for new feature types here after adding
* them to the above table.
*/
switch (feat_num) {
case DCCPF_SEND_LEV_RATE:
return DCCP_FEAT_SUPPORTED_MAX - 1;
}
return -1;
}
static u8 dccp_feat_type(u8 feat_num)
{
int idx = dccp_feat_index(feat_num);
if (idx < 0)
return FEAT_UNKNOWN;
return dccp_feat_table[idx].reconciliation;
}
static int dccp_feat_default_value(u8 feat_num)
{
int idx = dccp_feat_index(feat_num);
/*
* There are no default values for unknown features, so encountering a
* negative index here indicates a serious problem somewhere else.
*/
DCCP_BUG_ON(idx < 0);
return idx < 0 ? 0 : dccp_feat_table[idx].default_value;
}
/* copy constructor, fval must not already contain allocated memory */
static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
{
fval->sp.len = len;
if (fval->sp.len > 0) {
fval->sp.vec = kmemdup(val, len, gfp_any());
if (fval->sp.vec == NULL) {
fval->sp.len = 0;
return -ENOBUFS;
}
}
return 0;
}
static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
{
if (unlikely(val == NULL))
return;
if (dccp_feat_type(feat_num) == FEAT_SP)
kfree(val->sp.vec);
memset(val, 0, sizeof(*val));
}
static struct dccp_feat_entry *
dccp_feat_clone_entry(struct dccp_feat_entry const *original)
{
struct dccp_feat_entry *new;
u8 type = dccp_feat_type(original->feat_num);
if (type == FEAT_UNKNOWN)
return NULL;
new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any());
if (new == NULL)
return NULL;
if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val,
original->val.sp.vec,
original->val.sp.len)) {
kfree(new);
return NULL;
}
return new;
}
static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
{
if (entry != NULL) {
dccp_feat_val_destructor(entry->feat_num, &entry->val);
kfree(entry);
}
}
/*
* List management functions
*
* Feature negotiation lists rely on and maintain the following invariants:
* - each feat_num in the list is known, i.e. we know its type and default value
* - each feat_num/is_local combination is unique (old entries are overwritten)
* - SP values are always freshly allocated
* - list is sorted in increasing order of feature number (faster lookup)
*/
static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list,
u8 feat_num, bool is_local)
{
struct dccp_feat_entry *entry;
list_for_each_entry(entry, fn_list, node) {
if (entry->feat_num == feat_num && entry->is_local == is_local)
return entry;
else if (entry->feat_num > feat_num)
break;
}
return NULL;
}
/**
* dccp_feat_entry_new - Central list update routine (called by all others)
* @head: list to add to
* @feat: feature number
* @local: whether the local (1) or remote feature with number @feat is meant
* This is the only constructor and serves to ensure the above invariants.
*/
static struct dccp_feat_entry *
dccp_feat_entry_new(struct list_head *head, u8 feat, bool local)
{
struct dccp_feat_entry *entry;
list_for_each_entry(entry, head, node)
if (entry->feat_num == feat && entry->is_local == local) {
dccp_feat_val_destructor(entry->feat_num, &entry->val);
return entry;
} else if (entry->feat_num > feat) {
head = &entry->node;
break;
}
entry = kmalloc(sizeof(*entry), gfp_any());
if (entry != NULL) {
entry->feat_num = feat;
entry->is_local = local;
list_add_tail(&entry->node, head);
}
return entry;
}
/**
* dccp_feat_push_change - Add/overwrite a Change option in the list
* @fn_list: feature-negotiation list to update
* @feat: one of %dccp_feature_numbers
* @local: whether local (1) or remote (0) @feat_num is meant
* @needs_mandatory: whether to use Mandatory feature negotiation options
* @fval: pointer to NN/SP value to be inserted (will be copied)
*/
static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
u8 mandatory, dccp_feat_val *fval)
{
struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
if (new == NULL)
return -ENOMEM;
new->feat_num = feat;
new->is_local = local;
new->state = FEAT_INITIALISING;
new->needs_confirm = 0;
new->empty_confirm = 0;
new->val = *fval;
new->needs_mandatory = mandatory;
return 0;
}
static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
{
list_del(&entry->node);
dccp_feat_entry_destructor(entry);
}
void dccp_feat_list_purge(struct list_head *fn_list)
{
struct dccp_feat_entry *entry, *next;
list_for_each_entry_safe(entry, next, fn_list, node)
dccp_feat_entry_destructor(entry);
INIT_LIST_HEAD(fn_list);
}
EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
/* generate @to as full clone of @from - @to must not contain any nodes */
int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
{
struct dccp_feat_entry *entry, *new;
INIT_LIST_HEAD(to);
list_for_each_entry(entry, from, node) {
new = dccp_feat_clone_entry(entry);
if (new == NULL)
goto cloning_failed;
list_add_tail(&new->node, to);
}
return 0;
cloning_failed:
dccp_feat_list_purge(to);
return -ENOMEM;
}
/**
* dccp_feat_valid_nn_length - Enforce length constraints on NN options
* Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only,
* incoming options are accepted as long as their values are valid.
*/
static u8 dccp_feat_valid_nn_length(u8 feat_num)
{
if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */
return 2;
if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */
return 6;
return 0;
}
static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
{
switch (feat_num) {
case DCCPF_ACK_RATIO:
return val <= DCCPF_ACK_RATIO_MAX;
case DCCPF_SEQUENCE_WINDOW:
return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX;
}
return 0; /* feature unknown - so we can't tell */
}
/* check that SP values are within the ranges defined in RFC 4340 */
static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val)
{
switch (feat_num) {
case DCCPF_CCID:
return val == DCCPC_CCID2 || val == DCCPC_CCID3;
/* Type-check Boolean feature values: */
case DCCPF_SHORT_SEQNOS:
case DCCPF_ECN_INCAPABLE:
case DCCPF_SEND_ACK_VECTOR:
case DCCPF_SEND_NDP_COUNT:
case DCCPF_DATA_CHECKSUM:
case DCCPF_SEND_LEV_RATE:
return val < 2;
case DCCPF_MIN_CSUM_COVER:
return val < 16;
}
return 0; /* feature unknown */
}
static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
{
if (sp_list == NULL || sp_len < 1)
return 0;
while (sp_len--)
if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++))
return 0;
return 1;
}
/**
* dccp_feat_insert_opts - Generate FN options from current list state
* @skb: next sk_buff to be sent to the peer
* @dp: for client during handshake and general negotiation
* @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND)
*/
int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq,
struct sk_buff *skb)
{
struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
struct dccp_feat_entry *pos, *next;
u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN];
bool rpt;
/* put entries into @skb in the order they appear in the list */
list_for_each_entry_safe_reverse(pos, next, fn, node) {
opt = dccp_feat_genopt(pos);
type = dccp_feat_type(pos->feat_num);
rpt = false;
if (pos->empty_confirm) {
len = 0;
ptr = NULL;
} else {
if (type == FEAT_SP) {
len = pos->val.sp.len;
ptr = pos->val.sp.vec;
rpt = pos->needs_confirm;
} else if (type == FEAT_NN) {
len = dccp_feat_valid_nn_length(pos->feat_num);
ptr = nn_in_nbo;
dccp_encode_value_var(pos->val.nn, ptr, len);
} else {
DCCP_BUG("unknown feature %u", pos->feat_num);
return -1;
}
}
if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt))
return -1;
if (pos->needs_mandatory && dccp_insert_option_mandatory(skb))
return -1;
/*
* Enter CHANGING after transmitting the Change option (6.6.2).
*/
if (pos->state == FEAT_INITIALISING)
pos->state = FEAT_CHANGING;
}
return 0;
}
/**
* __feat_register_nn - Register new NN value on socket
* @fn: feature-negotiation list to register with
* @feat: an NN feature from %dccp_feature_numbers
* @mandatory: use Mandatory option if 1
* @nn_val: value to register (restricted to 4 bytes)
* Note that NN features are local by definition (RFC 4340, 6.3.2).
*/
static int __feat_register_nn(struct list_head *fn, u8 feat,
u8 mandatory, u64 nn_val)
{
dccp_feat_val fval = { .nn = nn_val };
if (dccp_feat_type(feat) != FEAT_NN ||
!dccp_feat_is_valid_nn_val(feat, nn_val))
return -EINVAL;
/* Don't bother with default values, they will be activated anyway. */
if (nn_val - (u64)dccp_feat_default_value(feat) == 0)
return 0;
return dccp_feat_push_change(fn, feat, 1, mandatory, &fval);
}
/**
* __feat_register_sp - Register new SP value/list on socket
* @fn: feature-negotiation list to register with
* @feat: an SP feature from %dccp_feature_numbers
* @is_local: whether the local (1) or the remote (0) @feat is meant
* @mandatory: use Mandatory option if 1
* @sp_val: SP value followed by optional preference list
* @sp_len: length of @sp_val in bytes
*/
static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
u8 mandatory, u8 const *sp_val, u8 sp_len)
{
dccp_feat_val fval;
if (dccp_feat_type(feat) != FEAT_SP ||
!dccp_feat_sp_list_ok(feat, sp_val, sp_len))
return -EINVAL;
/* Avoid negotiating alien CCIDs by only advertising supported ones */
if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len))
return -EOPNOTSUPP;
if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
return -ENOMEM;
return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
}
/**
* dccp_feat_register_sp - Register requests to change SP feature values
* @sk: client or listening socket
* @feat: one of %dccp_feature_numbers
* @is_local: whether the local (1) or remote (0) @feat is meant
* @list: array of preferred values, in descending order of preference
* @len: length of @list in bytes
*/
int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
u8 const *list, u8 len)
{ /* any changes must be registered before establishing the connection */
if (sk->sk_state != DCCP_CLOSED)
return -EISCONN;
if (dccp_feat_type(feat) != FEAT_SP)
return -EINVAL;
return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local,
0, list, len);
}
/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val)
{
/* any changes must be registered before establishing the connection */
if (sk->sk_state != DCCP_CLOSED)
return -EISCONN;
if (dccp_feat_type(feat) != FEAT_NN)
return -EINVAL;
return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val);
}
/*
* Tracking features whose value depend on the choice of CCID
*
* This is designed with an extension in mind so that a list walk could be done
* before activating any features. However, the existing framework was found to
* work satisfactorily up until now, the automatic verification is left open.
* When adding new CCIDs, add a corresponding dependency table here.
*/
static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local)
{
static const struct ccid_dependency ccid2_dependencies[2][2] = {
/*
* CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX
* feature and Send Ack Vector is an RX feature, `is_local'
* needs to be reversed.
*/
{ /* Dependencies of the receiver-side (remote) CCID2 */
{
.dependent_feat = DCCPF_SEND_ACK_VECTOR,
.is_local = true,
.is_mandatory = true,
.val = 1
},
{ 0, 0, 0, 0 }
},
{ /* Dependencies of the sender-side (local) CCID2 */
{
.dependent_feat = DCCPF_SEND_ACK_VECTOR,
.is_local = false,
.is_mandatory = true,
.val = 1
},
{ 0, 0, 0, 0 }
}
};
static const struct ccid_dependency ccid3_dependencies[2][5] = {
{ /*
* Dependencies of the receiver-side CCID3
*/
{ /* locally disable Ack Vectors */
.dependent_feat = DCCPF_SEND_ACK_VECTOR,
.is_local = true,
.is_mandatory = false,
.val = 0
},
{ /* see below why Send Loss Event Rate is on */
.dependent_feat = DCCPF_SEND_LEV_RATE,
.is_local = true,
.is_mandatory = true,
.val = 1
},
{ /* NDP Count is needed as per RFC 4342, 6.1.1 */
.dependent_feat = DCCPF_SEND_NDP_COUNT,
.is_local = false,
.is_mandatory = true,
.val = 1
},
{ 0, 0, 0, 0 },
},
{ /*
* CCID3 at the TX side: we request that the HC-receiver
* will not send Ack Vectors (they will be ignored, so
* Mandatory is not set); we enable Send Loss Event Rate
* (Mandatory since the implementation does not support
* the Loss Intervals option of RFC 4342, 8.6).
* The last two options are for peer's information only.
*/
{
.dependent_feat = DCCPF_SEND_ACK_VECTOR,
.is_local = false,
.is_mandatory = false,
.val = 0
},
{
.dependent_feat = DCCPF_SEND_LEV_RATE,
.is_local = false,
.is_mandatory = true,
.val = 1
},
{ /* this CCID does not support Ack Ratio */
.dependent_feat = DCCPF_ACK_RATIO,
.is_local = true,
.is_mandatory = false,
.val = 0
},
{ /* tell receiver we are sending NDP counts */
.dependent_feat = DCCPF_SEND_NDP_COUNT,
.is_local = true,
.is_mandatory = false,
.val = 1
},
{ 0, 0, 0, 0 }
}
};
switch (ccid) {
case DCCPC_CCID2:
return ccid2_dependencies[is_local];
case DCCPC_CCID3:
return ccid3_dependencies[is_local];
default:
return NULL;
}
}
/**
* dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID
* @fn: feature-negotiation list to update
* @id: CCID number to track
* @is_local: whether TX CCID (1) or RX CCID (0) is meant
* This function needs to be called after registering all other features.
*/
static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local)
{
const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local);
int i, rc = (table == NULL);
for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++)
if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP)
rc = __feat_register_sp(fn, table[i].dependent_feat,
table[i].is_local,
table[i].is_mandatory,
&table[i].val, 1);
else
rc = __feat_register_nn(fn, table[i].dependent_feat,
table[i].is_mandatory,
table[i].val);
return rc;
}
/**
* dccp_feat_finalise_settings - Finalise settings before starting negotiation
* @dp: client or listening socket (settings will be inherited)
* This is called after all registrations (socket initialisation, sysctls, and
* sockopt calls), and before sending the first packet containing Change options
* (ie. client-Request or server-Response), to ensure internal consistency.
*/
int dccp_feat_finalise_settings(struct dccp_sock *dp)
{
struct list_head *fn = &dp->dccps_featneg;
struct dccp_feat_entry *entry;
int i = 2, ccids[2] = { -1, -1 };
/*
* Propagating CCIDs:
* 1) not useful to propagate CCID settings if this host advertises more
* than one CCID: the choice of CCID may still change - if this is
* the client, or if this is the server and the client sends
* singleton CCID values.
* 2) since is that propagate_ccid changes the list, we defer changing
* the sorted list until after the traversal.
*/
list_for_each_entry(entry, fn, node)
if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1)
ccids[entry->is_local] = entry->val.sp.vec[0];
while (i--)
if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i))
return -1;
return 0;
}
/**
* dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features
* It is the server which resolves the dependencies once the CCID has been
* fully negotiated. If no CCID has been negotiated, it uses the default CCID.
*/
int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq)
{
struct list_head *fn = &dreq->dreq_featneg;
struct dccp_feat_entry *entry;
u8 is_local, ccid;
for (is_local = 0; is_local <= 1; is_local++) {
entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local);
if (entry != NULL && !entry->empty_confirm)
ccid = entry->val.sp.vec[0];
else
ccid = dccp_feat_default_value(DCCPF_CCID);
if (dccp_feat_propagate_ccid(fn, ccid, is_local))
return -1;
}
return 0;
}
static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
{
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_minisock *dmsk = dccp_msk(sk);
/* figure out if we are changing our CCID or the peer's */
const int rx = type == DCCPO_CHANGE_R;
const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
struct ccid *new_ccid;
/* Check if nothing is being changed. */
if (ccid_nr == new_ccid_nr)
return 0;
new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
if (new_ccid == NULL)
return -ENOMEM;
if (rx) {
ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
dp->dccps_hc_rx_ccid = new_ccid;
dmsk->dccpms_rx_ccid = new_ccid_nr;
} else {
ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
dp->dccps_hc_tx_ccid = new_ccid;
dmsk->dccpms_tx_ccid = new_ccid_nr;
}
return 0;
}
static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
{
dccp_feat_debug(type, feat, val);
switch (feat) {
case DCCPF_CCID:
return dccp_feat_update_ccid(sk, type, val);
default:
dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
dccp_feat_typename(type), feat);
break;
}
return 0;
}
static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
u8 *rpref, u8 rlen)
{
struct dccp_sock *dp = dccp_sk(sk);
u8 *spref, slen, *res = NULL;
int i, j, rc, agree = 1;
BUG_ON(rpref == NULL);
/* check if we are the black sheep */
if (dp->dccps_role == DCCP_ROLE_CLIENT) {
spref = rpref;
slen = rlen;
rpref = opt->dccpop_val;
rlen = opt->dccpop_len;
} else {
spref = opt->dccpop_val;
slen = opt->dccpop_len;
}
/*
* Now we have server preference list in spref and client preference in
* rpref
*/
BUG_ON(spref == NULL);
BUG_ON(rpref == NULL);
/* FIXME sanity check vals */
/* Are values in any order? XXX Lame "algorithm" here */
for (i = 0; i < slen; i++) {
for (j = 0; j < rlen; j++) {
if (spref[i] == rpref[j]) {
res = &spref[i];
break;
}
}
if (res)
break;
}
/* we didn't agree on anything */
if (res == NULL) {
/* confirm previous value */
switch (opt->dccpop_feat) {
case DCCPF_CCID:
/* XXX did i get this right? =P */
if (opt->dccpop_type == DCCPO_CHANGE_L)
res = &dccp_msk(sk)->dccpms_tx_ccid;
else
res = &dccp_msk(sk)->dccpms_rx_ccid;
break;
default:
DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
/* XXX implement res */
return -EFAULT;
}
dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
agree = 0; /* this is used for mandatory options... */
}
/* need to put result and our preference list */
rlen = 1 + opt->dccpop_len;
rpref = kmalloc(rlen, GFP_ATOMIC);
if (rpref == NULL)
return -ENOMEM;
*rpref = *res;
memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
/* put it in the "confirm queue" */
if (opt->dccpop_sc == NULL) {
opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
if (opt->dccpop_sc == NULL) {
kfree(rpref);
return -ENOMEM;
}
} else {
/* recycle the confirm slot */
BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
kfree(opt->dccpop_sc->dccpoc_val);
dccp_pr_debug("recycling confirm slot\n");
}
memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
opt->dccpop_sc->dccpoc_val = rpref;
opt->dccpop_sc->dccpoc_len = rlen;
/* update the option on our side [we are about to send the confirm] */
rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
if (rc) {
kfree(opt->dccpop_sc->dccpoc_val);
kfree(opt->dccpop_sc);
opt->dccpop_sc = NULL;
return rc;
}
dccp_pr_debug("Will confirm %d\n", *rpref);
/* say we want to change to X but we just got a confirm X, suppress our
* change
*/
if (!opt->dccpop_conf) {
if (*opt->dccpop_val == *res)
opt->dccpop_conf = 1;
dccp_pr_debug("won't ask for change of same feature\n");
}
return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
}
static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
{
struct dccp_minisock *dmsk = dccp_msk(sk);
struct dccp_opt_pend *opt;
int rc = 1;
u8 t;
/*
* We received a CHANGE. We gotta match it against our own preference
* list. If we got a CHANGE_R it means it's a change for us, so we need
* to compare our CHANGE_L list.
*/
if (type == DCCPO_CHANGE_L)
t = DCCPO_CHANGE_R;
else
t = DCCPO_CHANGE_L;
/* find our preference list for this feature */
list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
if (opt->dccpop_type != t || opt->dccpop_feat != feature)
continue;
/* find the winner from the two preference lists */
rc = dccp_feat_reconcile(sk, opt, val, len);
break;
}
/* We didn't deal with the change. This can happen if we have no
* preference list for the feature. In fact, it just shouldn't
* happen---if we understand a feature, we should have a preference list
* with at least the default value.
*/
BUG_ON(rc == 1);
return rc;
}
static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
{
struct dccp_opt_pend *opt;
struct dccp_minisock *dmsk = dccp_msk(sk);
u8 *copy;
int rc;
/* 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;
}
/* XXX sanity check opt val */
/* copy option so we can confirm it */
opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
if (opt == NULL)
return -ENOMEM;
copy = kmemdup(val, len, GFP_ATOMIC);
if (copy == NULL) {
kfree(opt);
return -ENOMEM;
}
opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
opt->dccpop_feat = feature;
opt->dccpop_val = copy;
opt->dccpop_len = len;
/* change feature */
rc = dccp_feat_update(sk, type, feature, *val);
if (rc) {
kfree(opt->dccpop_val);
kfree(opt);
return rc;
}
dccp_feat_debug(type, feature, *copy);
list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
return 0;
}
static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
u8 type, u8 feature)
{
/* XXX check if other confirms for that are queued and recycle slot */
struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
if (opt == NULL) {
/* XXX what do we do? Ignoring should be fine. It's a change
* after all =P
*/
return;
}
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:
DCCP_WARN("invalid type %d\n", type);
kfree(opt);
return;
}
opt->dccpop_feat = feature;
opt->dccpop_val = NULL;
opt->dccpop_len = 0;
/* change feature */
dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
}
static void dccp_feat_flush_confirm(struct sock *sk)
{
struct dccp_minisock *dmsk = dccp_msk(sk);
/* Check if there is anything to confirm in the first place */
int yes = !list_empty(&dmsk->dccpms_conf);
if (!yes) {
struct dccp_opt_pend *opt;
list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
if (opt->dccpop_conf) {
yes = 1;
break;
}
}
}
if (!yes)
return;
/* OK there is something to confirm... */
/* XXX check if packet is in flight? Send delayed ack?? */
if (sk->sk_state == DCCP_OPEN)
dccp_send_ack(sk);
}
int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
{
int rc;
/* Ignore Change requests other than during connection setup */
if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
return 0;
dccp_feat_debug(type, feature, *val);
/* figure out if it's SP or NN feature */
switch (feature) {
/* deal with SP features */
case DCCPF_CCID:
rc = dccp_feat_sp(sk, type, feature, val, len);
break;
/* deal with NN features */
case DCCPF_ACK_RATIO:
rc = dccp_feat_nn(sk, type, feature, val, len);
break;
/* XXX implement other features */
default:
dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
dccp_feat_typename(type), feature);
rc = -EFAULT;
break;
}
/* check if there were problems changing features */
if (rc) {
/* If we don't agree on SP, we sent a confirm for old value.
* However we propagate rc to caller in case option was
* mandatory
*/
if (rc != DCCP_FEAT_SP_NOAGREE)
dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
}
/* generate the confirm [if required] */
dccp_feat_flush_confirm(sk);
return rc;
}
EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
u8 *val, u8 len)
{
u8 t;
struct dccp_opt_pend *opt;
struct dccp_minisock *dmsk = dccp_msk(sk);
int found = 0;
int all_confirmed = 1;
/* Ignore Confirm options other than during connection setup */
if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
return 0;
dccp_feat_debug(type, feature, *val);
/* locate our change request */
switch (type) {
case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
default: DCCP_WARN("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) {
found = 1;
dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
/* XXX do sanity check */
opt->dccpop_conf = 1;
/* We got a confirmation---change the option */
dccp_feat_update(sk, opt->dccpop_type,
opt->dccpop_feat, *val);
/* XXX check the return value of dccp_feat_update */
break;
}
if (!opt->dccpop_conf)
all_confirmed = 0;
}
if (!found)
dccp_pr_debug("%s(%d, ...) never requested\n",
dccp_feat_typename(type), feature);
return 0;
}
EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
void dccp_feat_clean(struct dccp_minisock *dmsk)
{
struct dccp_opt_pend *opt, *next;
list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
dccpop_node) {
BUG_ON(opt->dccpop_val == NULL);
kfree(opt->dccpop_val);
if (opt->dccpop_sc != NULL) {
BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
kfree(opt->dccpop_sc->dccpoc_val);
kfree(opt->dccpop_sc);
}
kfree(opt);
}
INIT_LIST_HEAD(&dmsk->dccpms_pending);
list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
BUG_ON(opt == NULL);
if (opt->dccpop_val != NULL)
kfree(opt->dccpop_val);
kfree(opt);
}
INIT_LIST_HEAD(&dmsk->dccpms_conf);
}
EXPORT_SYMBOL_GPL(dccp_feat_clean);
/* this is to be called only when a listening sock creates its child. It is
* assumed by the function---the confirm is not duplicated, but rather it is
* "passed on".
*/
int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
{
struct dccp_minisock *olddmsk = dccp_msk(oldsk);
struct dccp_minisock *newdmsk = dccp_msk(newsk);
struct dccp_opt_pend *opt;
int rc = 0;
INIT_LIST_HEAD(&newdmsk->dccpms_pending);
INIT_LIST_HEAD(&newdmsk->dccpms_conf);
list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
struct dccp_opt_pend *newopt;
/* copy the value of the option */
u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
if (val == NULL)
goto out_clean;
newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
if (newopt == NULL) {
kfree(val);
goto out_clean;
}
/* insert the option */
newopt->dccpop_val = val;
list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
/* XXX what happens with backlogs and multiple connections at
* once...
*/
/* the master socket no longer needs to worry about confirms */
opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
/* reset state for a new socket */
opt->dccpop_conf = 0;
}
/* XXX not doing anything about the conf queue */
out:
return rc;
out_clean:
dccp_feat_clean(newdmsk);
rc = -ENOMEM;
goto out;
}
EXPORT_SYMBOL_GPL(dccp_feat_clone);
int dccp_feat_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_minisock *dmsk = dccp_msk(sk);
int rc;
INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */
INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */
/* CCID L */
rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
&dmsk->dccpms_tx_ccid, 1);
if (rc)
goto out;
/* CCID R */
rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
&dmsk->dccpms_rx_ccid, 1);
if (rc)
goto out;
/* Ack ratio */
rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
dp->dccps_l_ack_ratio);
out:
return rc;
}
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_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
return feature_names[DCCPF_RESERVED];
if (feat == DCCPF_SEND_LEV_RATE)
return "Send Loss Event Rate";
if (feat >= DCCPF_MIN_CCID_SPECIFIC)
return "CCID-specific";
return feature_names[feat];
}
EXPORT_SYMBOL_GPL(dccp_feat_name);
#endif /* CONFIG_IP_DCCP_DEBUG */