dccp: Clean up old feature-negotiation infrastructure

The code removed by this patch is no longer referenced or used, the added
lines update documentation and copyrights.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>

2 files changed, 12 insertions, 505 deletions

diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index f78bd357b5b1..6c82dea409d9 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -1,8 +1,13 @@
 /*
  *  net/dccp/feat.c
  *
- *  An implementation of the DCCP protocol
- *  Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *  Feature negotiation for the DCCP protocol (RFC 4340, section 6)
+ *
+ *  Copyright (c) 2008 The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk>
+ *  Rewrote from scratch, some bits from earlier code by
+ *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
  *
  *  ASSUMPTIONS
  *  -----------
@@ -17,14 +22,10 @@
  *  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)
-
 /*
  * Feature activation handlers.
  *
@@ -805,51 +806,6 @@ int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq)
         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;
-}
-
 /* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */
 static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen)
 {
@@ -919,453 +875,6 @@ static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len,
         return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len);
 }
 
-#ifdef __this_is_the_old_framework_and_will_be_removed_later_in_a_subsequent_patch
-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:
-                /* XXX Obsoleted by next patch
-                rc = dccp_feat_sp(sk, type, feature, val, len); */
-                break;
-
-        /* deal with NN features */
-        case DCCPF_ACK_RATIO:
-                /* XXX Obsoleted by next patch
-                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);
-#endif  /* (later) */
-
-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);
-
 /**
  * dccp_feat_change_recv  -  Process incoming ChangeL/R options
  * @fn: feature-negotiation list to update
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
index 618bed935b33..177e9c39ea9f 100644
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -3,14 +3,14 @@
 /*
  *  net/dccp/feat.h
  *
- *  An implementation of the DCCP protocol
+ *  Feature negotiation for the DCCP protocol (RFC 4340, section 6)
+ *  Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk>
  *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
  *
- *      This program is free software; you can redistribute it and/or modify it
- *      under the terms of the GNU General Public License version 2 as
- *      published by the Free Software Foundation.
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
  */
-
 #include <linux/types.h>
 #include "dccp.h"
 
@@ -117,8 +117,6 @@ extern int  dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
 extern int  dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
 extern int  dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
                                     u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
-extern void dccp_feat_clean(struct dccp_minisock *dmsk);
-extern int  dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
 extern int  dccp_feat_clone_list(struct list_head const *, struct list_head *);
 extern int  dccp_feat_init(struct sock *sk);