/* * net/dccp/feat.c * * An implementation of the DCCP protocol * Andrea Bittau <a.bittau@cs.ucl.ac.uk> * * ASSUMPTIONS * ----------- * 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) int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, u8 *val, u8 len, gfp_t gfp) { struct dccp_opt_pend *opt; dccp_feat_debug(type, feature, *val); if (len > 3) { DCCP_WARN("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) { /* ok we found a negotiation for this option already */ if (opt->dccpop_feat == feature && opt->dccpop_type == type) { dccp_pr_debug("Replacing old\n"); /* replace */ BUG_ON(opt->dccpop_val == NULL); kfree(opt->dccpop_val); opt->dccpop_val = val; opt->dccpop_len = len; opt->dccpop_conf = 0; return 0; } } /* negotiation for a new feature */ opt = kmalloc(sizeof(*opt), gfp); if (opt == NULL) return -ENOMEM; opt->dccpop_type = type; opt->dccpop_feat = feature; opt->dccpop_len = len; opt->dccpop_val = val; opt->dccpop_conf = 0; opt->dccpop_sc = NULL; BUG_ON(opt->dccpop_val == NULL); list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending); return 0; } EXPORT_SYMBOL_GPL(dccp_feat_change); 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; 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; 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; } /* fix re-transmit timer */ /* XXX gotta make sure that no option negotiation occurs during * connection shutdown. Consider that the CLOSEREQ is sent and timer is * on. if all options are confirmed it might kill timer which should * remain alive until close is received. */ if (all_confirmed) { dccp_pr_debug("clear feat negotiation timer %p\n", sk); inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); } 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); static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat, u8 *val, u8 len) { int rc = -ENOMEM; u8 *copy = kmemdup(val, len, GFP_KERNEL); if (copy != NULL) { rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL); if (rc) kfree(copy); } return rc; } int dccp_feat_init(struct dccp_minisock *dmsk) { int rc; INIT_LIST_HEAD(&dmsk->dccpms_pending); INIT_LIST_HEAD(&dmsk->dccpms_conf); /* CCID L */ rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID, &dmsk->dccpms_tx_ccid, 1); if (rc) goto out; /* CCID R */ rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID, &dmsk->dccpms_rx_ccid, 1); if (rc) goto out; /* Ack ratio */ rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO, &dmsk->dccpms_ack_ratio, 1); 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_MIN_CCID_SPECIFIC) return "CCID-specific"; return feature_names[feat]; } EXPORT_SYMBOL_GPL(dccp_feat_name); #endif /* CONFIG_IP_DCCP_DEBUG */