Commit 1fd07f33 authored by Andreas Roeseler's avatar Andreas Roeseler Committed by David S. Miller
Browse files

ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages 

This patch builds off of commit 2b246b25
and adds functionality to respond to ICMPV6 PROBE requests.

Add icmp_build_probe function to construct PROBE requests for both
ICMPV4 and ICMPV6.

Modify icmpv6_rcv to detect ICMPV6 PROBE messages and call the
icmpv6_echo_reply handler.

Modify icmpv6_echo_reply to build a PROBE response message based on the
queried interface.

This patch has been tested using a branch of the iputils git repo which can
be found here: https://github.com/Juniper-Clinic-2020/iputils/tree/probe-request



Signed-off-by: default avatarAndreas Roeseler <andreas.a.roeseler@gmail.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 83300c69

include/net/icmp.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -57,5 +57,6 @@ int icmp_rcv(struct sk_buff *skb); 
int icmp_err(struct sk_buff *skb, u32 info);

int icmp_err(struct sk_buff *skb, u32 info);

int icmp_init(void);

int icmp_init(void);

void icmp_out_count(struct net *net, unsigned char type);

void icmp_out_count(struct net *net, unsigned char type);

bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr);





#endif	/* _ICMP_H */
 
#endif	/* _ICMP_H */

net/ipv4/icmp.c

+41 −22
Original line number Original line Diff line number Diff line
@@ -993,14 +993,8 @@ static bool icmp_redirect(struct sk_buff *skb) 




static bool icmp_echo(struct sk_buff *skb)

static bool icmp_echo(struct sk_buff *skb)

{

{

	struct icmp_ext_hdr *ext_hdr, _ext_hdr;

	struct icmp_ext_echo_iio *iio, _iio;

	struct icmp_bxm icmp_param;

	struct icmp_bxm icmp_param;

	struct net_device *dev;

	char buff[IFNAMSIZ];

	struct net *net;

	struct net *net;

	u16 ident_len;

	u8 status;





	net = dev_net(skb_dst(skb)->dev);

	net = dev_net(skb_dst(skb)->dev);

	/* should there be an ICMP stat for ignored echos? */

	/* should there be an ICMP stat for ignored echos? */
@@ -1013,20 +1007,46 @@ static bool icmp_echo(struct sk_buff *skb) 
	icmp_param.data_len	   = skb->len;

	icmp_param.data_len	   = skb->len;

	icmp_param.head_len	   = sizeof(struct icmphdr);

	icmp_param.head_len	   = sizeof(struct icmphdr);





	if (icmp_param.data.icmph.type == ICMP_ECHO) {

	if (icmp_param.data.icmph.type == ICMP_ECHO)

		icmp_param.data.icmph.type = ICMP_ECHOREPLY;

		icmp_param.data.icmph.type = ICMP_ECHOREPLY;

		goto send_reply;

	else if (!icmp_build_probe(skb, &icmp_param.data.icmph))

		return true;



	icmp_reply(&icmp_param, skb);

	return true;

}

}



/*	Helper for icmp_echo and icmpv6_echo_reply.

 *	Searches for net_device that matches PROBE interface identifier

 *		and builds PROBE reply message in icmphdr.

 *

 *	Returns false if PROBE responses are disabled via sysctl

 */



bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)

{

	struct icmp_ext_hdr *ext_hdr, _ext_hdr;

	struct icmp_ext_echo_iio *iio, _iio;

	struct net *net = dev_net(skb->dev);

	struct net_device *dev;

	char buff[IFNAMSIZ];

	u16 ident_len;

	u8 status;



	if (!net->ipv4.sysctl_icmp_echo_enable_probe)

	if (!net->ipv4.sysctl_icmp_echo_enable_probe)

		return true;

		return false;



	/* We currently only support probing interfaces on the proxy node

	/* We currently only support probing interfaces on the proxy node

	 * Check to ensure L-bit is set

	 * Check to ensure L-bit is set

	 */

	 */

	if (!(ntohs(icmp_param.data.icmph.un.echo.sequence) & 1))

	if (!(ntohs(icmphdr->un.echo.sequence) & 1))

		return true;

		return false;

	/* Clear status bits in reply message */

	/* Clear status bits in reply message */

	icmp_param.data.icmph.un.echo.sequence &= htons(0xFF00);

	icmphdr->un.echo.sequence &= htons(0xFF00);

	icmp_param.data.icmph.type = ICMP_EXT_ECHOREPLY;

	if (icmphdr->type == ICMP_EXT_ECHO)

		icmphdr->type = ICMP_EXT_ECHOREPLY;

	else

		icmphdr->type = ICMPV6_EXT_ECHO_REPLY;

	ext_hdr = skb_header_pointer(skb, 0, sizeof(_ext_hdr), &_ext_hdr);

	ext_hdr = skb_header_pointer(skb, 0, sizeof(_ext_hdr), &_ext_hdr);

	/* Size of iio is class_type dependent.

	/* Size of iio is class_type dependent.

	 * Only check header here and assign length based on ctype in the switch statement

	 * Only check header here and assign length based on ctype in the switch statement
@@ -1087,8 +1107,8 @@ static bool icmp_echo(struct sk_buff *skb) 
		goto send_mal_query;

		goto send_mal_query;

	}

	}

	if (!dev) {

	if (!dev) {

		icmp_param.data.icmph.code = ICMP_EXT_CODE_NO_IF;

		icmphdr->code = ICMP_EXT_CODE_NO_IF;

		goto send_reply;

		return true;

	}

	}

	/* Fill bits in reply message */

	/* Fill bits in reply message */

	if (dev->flags & IFF_UP)

	if (dev->flags & IFF_UP)
@@ -1098,14 +1118,13 @@ static bool icmp_echo(struct sk_buff *skb) 
	if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list))

	if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list))

		status |= ICMP_EXT_ECHOREPLY_IPV6;

		status |= ICMP_EXT_ECHOREPLY_IPV6;

	dev_put(dev);

	dev_put(dev);

	icmp_param.data.icmph.un.echo.sequence |= htons(status);

	icmphdr->un.echo.sequence |= htons(status);

send_reply:

	icmp_reply(&icmp_param, skb);

	return true;

	return true;

send_mal_query:

send_mal_query:

	icmp_param.data.icmph.code = ICMP_EXT_CODE_MAL_QUERY;

	icmphdr->code = ICMP_EXT_CODE_MAL_QUERY;

	goto send_reply;

	return true;

}

}

EXPORT_SYMBOL_GPL(icmp_build_probe);





/*

/*

 *	Handle ICMP Timestamp requests.

 *	Handle ICMP Timestamp requests.

net/ipv6/icmp.c

+18 −3
Original line number Original line Diff line number Diff line
@@ -725,6 +725,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 
	struct ipcm6_cookie ipc6;

	struct ipcm6_cookie ipc6;

	u32 mark = IP6_REPLY_MARK(net, skb->mark);

	u32 mark = IP6_REPLY_MARK(net, skb->mark);

	bool acast;

	bool acast;

	u8 type;





	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&

	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&

	    net->ipv6.sysctl.icmpv6_echo_ignore_multicast)

	    net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
@@ -740,8 +741,13 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 
	    !(net->ipv6.sysctl.anycast_src_echo_reply && acast))

	    !(net->ipv6.sysctl.anycast_src_echo_reply && acast))

		saddr = NULL;

		saddr = NULL;





	if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)

		type = ICMPV6_EXT_ECHO_REPLY;

	else

		type = ICMPV6_ECHO_REPLY;



	memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));

	memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));

	tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;

	tmp_hdr.icmp6_type = type;





	memset(&fl6, 0, sizeof(fl6));

	memset(&fl6, 0, sizeof(fl6));

	if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)

	if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
@@ -752,7 +758,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 
	if (saddr)

	if (saddr)

		fl6.saddr = *saddr;

		fl6.saddr = *saddr;

	fl6.flowi6_oif = icmp6_iif(skb);

	fl6.flowi6_oif = icmp6_iif(skb);

	fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;

	fl6.fl6_icmp_type = type;

	fl6.flowi6_mark = mark;

	fl6.flowi6_mark = mark;

	fl6.flowi6_uid = sock_net_uid(net, NULL);

	fl6.flowi6_uid = sock_net_uid(net, NULL);

	security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));

	security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
@@ -783,13 +789,17 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 




	msg.skb = skb;

	msg.skb = skb;

	msg.offset = 0;

	msg.offset = 0;

	msg.type = ICMPV6_ECHO_REPLY;

	msg.type = type;





	ipcm6_init_sk(&ipc6, np);

	ipcm6_init_sk(&ipc6, np);

	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);

	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);

	ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));

	ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));

	ipc6.sockc.mark = mark;

	ipc6.sockc.mark = mark;





	if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)

		if (!icmp_build_probe(skb, (struct icmphdr *)&tmp_hdr))

			goto out_dst_release;



	if (ip6_append_data(sk, icmpv6_getfrag, &msg,

	if (ip6_append_data(sk, icmpv6_getfrag, &msg,

			    skb->len + sizeof(struct icmp6hdr),

			    skb->len + sizeof(struct icmp6hdr),

			    sizeof(struct icmp6hdr), &ipc6, &fl6,

			    sizeof(struct icmp6hdr), &ipc6, &fl6,
@@ -911,6 +921,11 @@ static int icmpv6_rcv(struct sk_buff *skb) 
		if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)

		if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)

			icmpv6_echo_reply(skb);

			icmpv6_echo_reply(skb);

		break;

		break;

	case ICMPV6_EXT_ECHO_REQUEST:

		if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&

		    net->ipv4.sysctl_icmp_echo_enable_probe)

			icmpv6_echo_reply(skb);

		break;





	case ICMPV6_ECHO_REPLY:

	case ICMPV6_ECHO_REPLY:

		success = ping_rcv(skb);

		success = ping_rcv(skb);