dccp: Registration routines for changing feature values
Two registration routines, for SP and NN features, are provided by this patch, replacing a previous routine which was used for both feature types. These are internal-only routines and therefore start with `__feat_register'. It further exports the known limits of Sequence Window and Ack Ratio as symbolic constants. 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>
This commit is contained in:
Gerrit Renker
David S. Miller
parent
f74e91b6cc
commit
e8ef967a54
4 changed files with 197 additions and 28 deletions
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@ -25,7 +25,7 @@
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/*
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* This implementation should follow RFC 4341
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*/
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#include "../feat.h"
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#include "../ccid.h"
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#include "../dccp.h"
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#include "ccid2.h"
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@ -147,8 +147,8 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
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DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
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val = max_ratio;
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}
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if (val > 0xFFFF) /* RFC 4340, 11.3 */
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val = 0xFFFF;
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if (val > DCCPF_ACK_RATIO_MAX)
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val = DCCPF_ACK_RATIO_MAX;
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if (val == dp->dccps_l_ack_ratio)
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return;
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192
net/dccp/feat.c
192
net/dccp/feat.c
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@ -92,6 +92,18 @@ static u8 dccp_feat_type(u8 feat_num)
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return dccp_feat_table[idx].reconciliation;
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}
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static int dccp_feat_default_value(u8 feat_num)
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{
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int idx = dccp_feat_index(feat_num);
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/*
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* There are no default values for unknown features, so encountering a
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* negative index here indicates a serious problem somewhere else.
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*/
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DCCP_BUG_ON(idx < 0);
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return idx < 0 ? 0 : dccp_feat_table[idx].default_value;
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}
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/* copy constructor, fval must not already contain allocated memory */
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static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
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{
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@ -155,6 +167,63 @@ static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
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* - list is sorted in increasing order of feature number (faster lookup)
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*/
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/**
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* dccp_feat_entry_new - Central list update routine (called by all others)
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* @head: list to add to
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* @feat: feature number
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* @local: whether the local (1) or remote feature with number @feat is meant
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* This is the only constructor and serves to ensure the above invariants.
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*/
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static struct dccp_feat_entry *
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dccp_feat_entry_new(struct list_head *head, u8 feat, bool local)
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{
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struct dccp_feat_entry *entry;
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list_for_each_entry(entry, head, node)
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if (entry->feat_num == feat && entry->is_local == local) {
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dccp_feat_val_destructor(entry->feat_num, &entry->val);
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return entry;
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} else if (entry->feat_num > feat) {
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head = &entry->node;
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break;
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}
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entry = kmalloc(sizeof(*entry), gfp_any());
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if (entry != NULL) {
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entry->feat_num = feat;
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entry->is_local = local;
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list_add_tail(&entry->node, head);
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}
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return entry;
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}
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/**
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* dccp_feat_push_change - Add/overwrite a Change option in the list
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* @fn_list: feature-negotiation list to update
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* @feat: one of %dccp_feature_numbers
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* @local: whether local (1) or remote (0) @feat_num is meant
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* @needs_mandatory: whether to use Mandatory feature negotiation options
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* @fval: pointer to NN/SP value to be inserted (will be copied)
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*/
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static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
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u8 mandatory, dccp_feat_val *fval)
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{
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struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
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if (new == NULL)
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return -ENOMEM;
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new->feat_num = feat;
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new->is_local = local;
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new->state = FEAT_INITIALISING;
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new->needs_confirm = 0;
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new->empty_confirm = 0;
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new->val = *fval;
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new->needs_mandatory = mandatory;
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return 0;
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}
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static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
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{
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list_del(&entry->node);
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@ -190,6 +259,95 @@ int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
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return -ENOMEM;
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}
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static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
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{
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switch (feat_num) {
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case DCCPF_ACK_RATIO:
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return val <= DCCPF_ACK_RATIO_MAX;
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case DCCPF_SEQUENCE_WINDOW:
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return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX;
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}
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return 0; /* feature unknown - so we can't tell */
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}
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/* check that SP values are within the ranges defined in RFC 4340 */
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static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val)
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{
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switch (feat_num) {
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case DCCPF_CCID:
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return val == DCCPC_CCID2 || val == DCCPC_CCID3;
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/* Type-check Boolean feature values: */
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case DCCPF_SHORT_SEQNOS:
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case DCCPF_ECN_INCAPABLE:
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case DCCPF_SEND_ACK_VECTOR:
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case DCCPF_SEND_NDP_COUNT:
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case DCCPF_DATA_CHECKSUM:
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case DCCPF_SEND_LEV_RATE:
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return val < 2;
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case DCCPF_MIN_CSUM_COVER:
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return val < 16;
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}
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return 0; /* feature unknown */
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}
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static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
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{
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if (sp_list == NULL || sp_len < 1)
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return 0;
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while (sp_len--)
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if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++))
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return 0;
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return 1;
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}
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/**
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* __feat_register_nn - Register new NN value on socket
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* @fn: feature-negotiation list to register with
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* @feat: an NN feature from %dccp_feature_numbers
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* @mandatory: use Mandatory option if 1
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* @nn_val: value to register (restricted to 4 bytes)
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* Note that NN features are local by definition (RFC 4340, 6.3.2).
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*/
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static int __feat_register_nn(struct list_head *fn, u8 feat,
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u8 mandatory, u64 nn_val)
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{
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dccp_feat_val fval = { .nn = nn_val };
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if (dccp_feat_type(feat) != FEAT_NN ||
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!dccp_feat_is_valid_nn_val(feat, nn_val))
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return -EINVAL;
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/* Don't bother with default values, they will be activated anyway. */
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if (nn_val - (u64)dccp_feat_default_value(feat) == 0)
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return 0;
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return dccp_feat_push_change(fn, feat, 1, mandatory, &fval);
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}
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/**
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* __feat_register_sp - Register new SP value/list on socket
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* @fn: feature-negotiation list to register with
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* @feat: an SP feature from %dccp_feature_numbers
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* @is_local: whether the local (1) or the remote (0) @feat is meant
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* @mandatory: use Mandatory option if 1
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* @sp_val: SP value followed by optional preference list
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* @sp_len: length of @sp_val in bytes
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*/
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static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
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u8 mandatory, u8 const *sp_val, u8 sp_len)
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{
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dccp_feat_val fval;
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if (dccp_feat_type(feat) != FEAT_SP ||
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!dccp_feat_sp_list_ok(feat, sp_val, sp_len))
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return -EINVAL;
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if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
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return -ENOMEM;
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return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
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}
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int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
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u8 *val, u8 len, gfp_t gfp)
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{
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@ -726,42 +884,30 @@ int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
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EXPORT_SYMBOL_GPL(dccp_feat_clone);
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static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
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u8 *val, u8 len)
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{
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int rc = -ENOMEM;
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u8 *copy = kmemdup(val, len, GFP_KERNEL);
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if (copy != NULL) {
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rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
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if (rc)
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kfree(copy);
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}
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return rc;
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}
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int dccp_feat_init(struct dccp_minisock *dmsk)
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int dccp_feat_init(struct sock *sk)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct dccp_minisock *dmsk = dccp_msk(sk);
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int rc;
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INIT_LIST_HEAD(&dmsk->dccpms_pending);
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INIT_LIST_HEAD(&dmsk->dccpms_conf);
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INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */
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INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */
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/* CCID L */
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rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
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&dmsk->dccpms_tx_ccid, 1);
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rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
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&dmsk->dccpms_tx_ccid, 1);
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if (rc)
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goto out;
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/* CCID R */
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rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
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&dmsk->dccpms_rx_ccid, 1);
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rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
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&dmsk->dccpms_rx_ccid, 1);
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if (rc)
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goto out;
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/* Ack ratio */
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rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
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&dmsk->dccpms_ack_ratio, 1);
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rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
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dmsk->dccpms_ack_ratio);
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out:
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return rc;
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}
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@ -14,6 +14,15 @@
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#include <linux/types.h>
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#include "dccp.h"
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/*
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* Known limit values
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*/
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/* Ack Ratio takes 2-byte integer values (11.3) */
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#define DCCPF_ACK_RATIO_MAX 0xFFFF
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/* Wmin=32 and Wmax=2^46-1 from 7.5.2 */
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#define DCCPF_SEQ_WMIN 32
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#define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull
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enum dccp_feat_type {
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FEAT_AT_RX = 1, /* located at RX side of half-connection */
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FEAT_AT_TX = 2, /* located at TX side of half-connection */
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@ -75,6 +84,20 @@ static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry)
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return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R;
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}
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/**
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* struct ccid_dependency - Track changes resulting from choosing a CCID
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* @dependent_feat: one of %dccp_feature_numbers
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* @is_local: local (1) or remote (0) @dependent_feat
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* @is_mandatory: whether presence of @dependent_feat is mission-critical or not
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* @val: corresponding default value for @dependent_feat (u8 is sufficient here)
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*/
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struct ccid_dependency {
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u8 dependent_feat;
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bool is_local:1,
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is_mandatory:1;
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u8 val;
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};
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#ifdef CONFIG_IP_DCCP_DEBUG
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extern const char *dccp_feat_typename(const u8 type);
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extern const char *dccp_feat_name(const u8 feat);
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@ -97,6 +120,6 @@ extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
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extern void dccp_feat_clean(struct dccp_minisock *dmsk);
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extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
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extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
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extern int dccp_feat_init(struct dccp_minisock *dmsk);
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extern int dccp_feat_init(struct sock *sk);
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#endif /* _DCCP_FEAT_H */
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@ -202,7 +202,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
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* setsockopt(CCIDs-I-want/accept). -acme
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*/
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if (likely(ctl_sock_initialized)) {
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int rc = dccp_feat_init(dmsk);
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int rc = dccp_feat_init(sk);
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if (rc)
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return rc;
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