[DCCP]: Initial feature negotiation implementation (afe00251) · Commits · 戴 / test

include/linux/dccp.h

+34 −1

Original line number	Diff line number	Diff line
		@@ -154,6 +154,10 @@ enum {
		DCCPO_MANDATORY = 1,
		DCCPO_MIN_RESERVED = 3,
		DCCPO_MAX_RESERVED = 31,
		DCCPO_CHANGE_L = 32,
		DCCPO_CONFIRM_L = 33,
		DCCPO_CHANGE_R = 34,
		DCCPO_CONFIRM_R = 35,
		DCCPO_NDP_COUNT = 37,
		DCCPO_ACK_VECTOR_0 = 38,
		DCCPO_ACK_VECTOR_1 = 39,
		@@ -168,7 +172,9 @@ enum {
		/* 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,
		/* 10-127 reserved */
		@@ -176,9 +182,18 @@ enum {
		DCCPF_MAX_CCID_SPECIFIC = 255,
		};

		/* this structure is argument to DCCP_SOCKOPT_CHANGE_X */
		struct dccp_so_feat {
		__u8 dccpsf_feat;
		__u8 *dccpsf_val;
		__u8 dccpsf_len;
		};

		/* DCCP socket options */
		#define DCCP_SOCKOPT_PACKET_SIZE 1
		#define DCCP_SOCKOPT_SERVICE 2
		#define DCCP_SOCKOPT_CHANGE_L 3
		#define DCCP_SOCKOPT_CHANGE_R 4
		#define DCCP_SOCKOPT_CCID_RX_INFO 128
		#define DCCP_SOCKOPT_CCID_TX_INFO 192

		@@ -314,8 +329,8 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)

		/* initial values for each feature */
		#define DCCPF_INITIAL_SEQUENCE_WINDOW 100
		/* FIXME: for now we're using CCID 2 (TCP-Like) */
		#define DCCPF_INITIAL_CCID 2
		#define DCCPF_INITIAL_ACK_RATIO 2
		#define DCCPF_INITIAL_SEND_ACK_VECTOR 1
		/* FIXME: for now we're default to 1 but it should really be 0 */
		#define DCCPF_INITIAL_SEND_NDP_COUNT 1
		@@ -335,6 +350,24 @@ struct dccp_options {
		__u8 dccpo_tx_ccid;
		__u8 dccpo_send_ack_vector;
		__u8 dccpo_send_ndp_count;
		__u8 dccpo_ack_ratio;
		struct list_head dccpo_pending;
		struct list_head dccpo_conf;
		};

		struct dccp_opt_conf {
		__u8 *dccpoc_val;
		__u8 dccpoc_len;
		};

		struct dccp_opt_pend {
		struct list_head dccpop_node;
		__u8 dccpop_type;
		__u8 dccpop_feat;
		__u8 *dccpop_val;
		__u8 dccpop_len;
		int dccpop_conf;
		struct dccp_opt_conf *dccpop_sc;
		};

		extern void __dccp_options_init(struct dccp_options *dccpo);

net/dccp/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -4,7 +4,7 @@ dccp_ipv6-y := ipv6.o

		obj-$(CONFIG_IP_DCCP) += dccp.o

		dccp-y := ccid.o input.o ipv4.o minisocks.o options.o output.o proto.o \
		dccp-y := ccid.o feat.o input.o ipv4.o minisocks.o options.o output.o proto.o \
		timer.o

		dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o

net/dccp/feat.c

0 → 100644

+554 −0

Original line number	Diff line number	Diff line
		/*
		* net/dccp/feat.c
		*
		* An implementation of the DCCP protocol
		* 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
		* as published by the Free Software Foundation; either version
		* 2 of the License, or (at your option) any later version.
		*/

		#include <linux/config.h>
		#include <linux/module.h>

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

		#define DCCP_FEAT_SP_NOAGREE (-123)

		int dccp_feat_change(struct sock sk, u8 type, u8 feature, u8 val, u8 len,
		gfp_t gfp)
		{
		struct dccp_sock *dp = dccp_sk(sk);
		struct dccp_opt_pend *opt;

		dccp_pr_debug("feat change type=%d feat=%d\n", type, feature);

		/* check if that feature is already being negotiated */
		list_for_each_entry(opt, &dp->dccps_options.dccpo_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, &dp->dccps_options.dccpo_pending);
		return 0;
		}

		EXPORT_SYMBOL_GPL(dccp_feat_change);

		/* XXX taking only u8 vals */
		static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
		{
		/* FIXME implement */
		dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val);
		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 */
		/* XXX assume values are 1 byte */
		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 = &dp->dccps_options.dccpo_tx_ccid;
		else
		res = &dp->dccps_options.dccpo_rx_ccid;
		break;

		default:
		WARN_ON(1); /* 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 */
		/* XXX assume 1 byte vals */
		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 = 0;
		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_sock *dp = dccp_sk(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, &dp->dccps_options.dccpo_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_sock *dp = dccp_sk(sk);
		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);
		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 = kmalloc(len, GFP_ATOMIC);
		if (copy == NULL) {
		kfree(opt);
		return -ENOMEM;
		}
		memcpy(copy, val, len);

		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_pr_debug("Confirming NN feature %d (val=%d)\n", feature, *copy);
		list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf);

		return 0;
		}

		static void dccp_feat_empty_confirm(struct sock *sk, u8 type, u8 feature)
		{
		struct dccp_sock *dp = dccp_sk(sk);
		/* 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;
		}

		opt->dccpop_type = type == DCCPO_CHANGE_L ? DCCPO_CONFIRM_R :
		DCCPO_CONFIRM_L;
		opt->dccpop_feat = feature;
		opt->dccpop_val = 0;
		opt->dccpop_len = 0;

		/* change feature */
		dccp_pr_debug("Empty confirm feature %d type %d\n", feature, type);
		list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf);
		}

		static void dccp_feat_flush_confirm(struct sock *sk)
		{
		struct dccp_sock *dp = dccp_sk(sk);
		/* Check if there is anything to confirm in the first place */
		int yes = !list_empty(&dp->dccps_options.dccpo_conf);

		if (!yes) {
		struct dccp_opt_pend *opt;

		list_for_each_entry(opt, &dp->dccps_options.dccpo_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_pr_debug("got feat change type=%d feat=%d\n", type, feature);

		/* 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:
		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(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_sock *dp = dccp_sk(sk);
		int rc = 1;
		int all_confirmed = 1;

		dccp_pr_debug("got feat confirm type=%d feat=%d\n", type, feature);

		/* XXX sanity check type & feat */

		/* locate our change request */
		t = type == DCCPO_CONFIRM_L ? DCCPO_CHANGE_R : DCCPO_CHANGE_L;

		list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
		dccpop_node) {
		if (!opt->dccpop_conf && opt->dccpop_type == t &&
		opt->dccpop_feat == feature) {
		/* we found it */
		/* 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);

		dccp_pr_debug("feat %d type %d confirmed %d\n",
		feature, type, *val);
		rc = 0;
		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 (rc)
		dccp_pr_debug("feat %d type %d never requested\n",
		feature, type);
		return 0;
		}

		EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);

		void dccp_feat_clean(struct sock *sk)
		{
		struct dccp_sock *dp = dccp_sk(sk);
		struct dccp_opt_pend opt, next;

		list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_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(&dp->dccps_options.dccpo_pending);

		list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_conf,
		dccpop_node) {
		BUG_ON(opt == NULL);
		if (opt->dccpop_val != NULL)
		kfree(opt->dccpop_val);
		kfree(opt);
		}
		INIT_LIST_HEAD(&dp->dccps_options.dccpo_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_sock *olddp = dccp_sk(oldsk);
		struct dccp_sock *newdp = dccp_sk(newsk);
		struct dccp_opt_pend *opt;
		int rc = 0;

		INIT_LIST_HEAD(&newdp->dccps_options.dccpo_pending);
		INIT_LIST_HEAD(&newdp->dccps_options.dccpo_conf);

		list_for_each_entry(opt, &olddp->dccps_options.dccpo_pending,
		dccpop_node) {
		struct dccp_opt_pend *newopt;
		/* copy the value of the option */
		u8 *val = kmalloc(opt->dccpop_len, GFP_ATOMIC);

		if (val == NULL)
		goto out_clean;
		memcpy(val, opt->dccpop_val, opt->dccpop_len);

		newopt = kmalloc(sizeof(*newopt), GFP_ATOMIC);
		if (newopt == NULL) {
		kfree(val);
		goto out_clean;
		}

		/* insert the option */
		memcpy(newopt, opt, sizeof(*newopt));
		newopt->dccpop_val = val;
		list_add_tail(&newopt->dccpop_node,
		&newdp->dccps_options.dccpo_pending);

		/* XXX what happens with backlogs and multiple connections at
		* once...
		*/
		/* the master socket no longer needs to worry about confirms */
		opt->dccpop_sc = 0; /* 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(newsk);
		rc = -ENOMEM;
		goto out;
		}

		EXPORT_SYMBOL_GPL(dccp_feat_clone);

		static int __dccp_feat_init(struct sock sk, u8 type, u8 feat, u8 val, u8 len)
		{
		int rc = -ENOMEM;
		u8 *copy = kmalloc(len, GFP_KERNEL);

		if (copy != NULL) {
		memcpy(copy, val, len);
		rc = dccp_feat_change(sk, type, feat, copy, len, GFP_KERNEL);
		if (rc)
		kfree(copy);
		}
		return rc;
		}

		int dccp_feat_init(struct sock *sk)
		{
		struct dccp_sock *dp = dccp_sk(sk);
		int rc;

		INIT_LIST_HEAD(&dp->dccps_options.dccpo_pending);
		INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf);

		/* CCID L */
		rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_CCID,
		&dp->dccps_options.dccpo_tx_ccid, 1);
		if (rc)
		goto out;

		/* CCID R */
		rc = __dccp_feat_init(sk, DCCPO_CHANGE_R, DCCPF_CCID,
		&dp->dccps_options.dccpo_rx_ccid, 1);
		if (rc)
		goto out;

		/* Ack ratio */
		rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
		&dp->dccps_options.dccpo_ack_ratio, 1);
		out:
		return rc;
		}

		EXPORT_SYMBOL_GPL(dccp_feat_init);

net/dccp/feat.h

0 → 100644

+28 −0

Original line number	Diff line number	Diff line
		#ifndef _DCCP_FEAT_H
		#define _DCCP_FEAT_H
		/*
		* net/dccp/feat.h
		*
		* An implementation of the DCCP protocol
		* 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.
		*/

		#include <linux/types.h>

		struct sock;

		extern int dccp_feat_change(struct sock *sk, u8 type, u8 feature,
		u8 *val, u8 len, gfp_t gfp);
		extern int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature,
		u8 *val, u8 len);
		extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
		u8 *val, u8 len);
		extern void dccp_feat_clean(struct sock *sk);
		extern int dccp_feat_clone(struct sock oldsk, struct sock newsk);
		extern int dccp_feat_init(struct sock *sk);

		#endif /* _DCCP_FEAT_H */

net/dccp/input.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -300,6 +300,9 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
		goto out_invalid_packet;
		}

		if (dccp_parse_options(sk, skb))
		goto out_invalid_packet;

		if (dp->dccps_options.dccpo_send_ack_vector &&
		dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
		DCCP_SKB_CB(skb)->dccpd_seq,

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