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Commit 91ed81f9 authored by Jonas Bonn's avatar Jonas Bonn Committed by David S. Miller
Browse files

gtp: support SGSN-side tunnels 



The GTP-tunnel driver is explicitly GGSN-side as it searches for PDP
contexts based on the incoming packets _destination_ address.  If we
want to place ourselves on the SGSN side of the  tunnel, then we want
to be identifying PDP contexts based on _source_ address.

Let it be noted that in a "real" configuration this module would never
be used:  the SGSN normally does not see IP packets as input.  The
justification for this functionality is for PGW load-testing applications
where the input to the SGSN is locally generally IP traffic.

This patch adds a "role" argument at GTP-link creation time to specify
whether we are on the GGSN or SGSN side of the tunnel; this flag is then
used to determine which part of the IP packet to use in determining
the PDP context.

Signed-off-by: default avatarJonas Bonn <jonas@southpole.se>
Acked-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: default avatarHarald Welte <laforge@gnumonks.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ae6336b5

drivers/net/gtp.c

+30 −12
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ struct gtp_dev { 


	struct net_device	*dev;



	unsigned int		role;

	unsigned int		hash_size;

	struct hlist_head	*tid_hash;

	struct hlist_head	*addr_hash;
@@ -154,8 +155,8 @@ static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr) 
	return NULL;

}



static bool gtp_check_src_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx,

				  unsigned int hdrlen)

static bool gtp_check_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx,

				  unsigned int hdrlen, unsigned int role)

{

	struct iphdr *iph;
@@ -164,27 +165,31 @@ static bool gtp_check_src_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx, 


	iph = (struct iphdr *)(skb->data + hdrlen);



	if (role == GTP_ROLE_SGSN)

		return iph->daddr == pctx->ms_addr_ip4.s_addr;

	else

		return iph->saddr == pctx->ms_addr_ip4.s_addr;

}



/* Check if the inner IP source address in this packet is assigned to any

/* Check if the inner IP address in this packet is assigned to any

 * existing mobile subscriber.

 */

static bool gtp_check_src_ms(struct sk_buff *skb, struct pdp_ctx *pctx,

			     unsigned int hdrlen)

static bool gtp_check_ms(struct sk_buff *skb, struct pdp_ctx *pctx,

			     unsigned int hdrlen, unsigned int role)

{

	switch (ntohs(skb->protocol)) {

	case ETH_P_IP:

		return gtp_check_src_ms_ipv4(skb, pctx, hdrlen);

		return gtp_check_ms_ipv4(skb, pctx, hdrlen, role);

	}

	return false;

}



static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb, unsigned int hdrlen)

static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb,

			unsigned int hdrlen, unsigned int role)

{

	struct pcpu_sw_netstats *stats;



	if (!gtp_check_src_ms(skb, pctx, hdrlen)) {

	if (!gtp_check_ms(skb, pctx, hdrlen, role)) {

		netdev_dbg(pctx->dev, "No PDP ctx for this MS\n");

		return 1;

	}
@@ -239,7 +244,7 @@ static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) 
		return 1;

	}



	return gtp_rx(pctx, skb, hdrlen);

	return gtp_rx(pctx, skb, hdrlen, gtp->role);

}



static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb)
@@ -281,7 +286,7 @@ static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) 
		return 1;

	}



	return gtp_rx(pctx, skb, hdrlen);

	return gtp_rx(pctx, skb, hdrlen, gtp->role);

}



static void gtp_encap_destroy(struct sock *sk)
@@ -481,7 +486,11 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev, 
	 * Prepend PDP header with TEI/TID from PDP ctx.

	 */

	iph = ip_hdr(skb);

	if (gtp->role == GTP_ROLE_SGSN)

		pctx = ipv4_pdp_find(gtp, iph->saddr);

	else

		pctx = ipv4_pdp_find(gtp, iph->daddr);



	if (!pctx) {

		netdev_dbg(dev, "no PDP ctx found for %pI4, skip\n",

			   &iph->daddr);
@@ -685,6 +694,7 @@ static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = { 
	[IFLA_GTP_FD0]			= { .type = NLA_U32 },

	[IFLA_GTP_FD1]			= { .type = NLA_U32 },

	[IFLA_GTP_PDP_HASHSIZE]		= { .type = NLA_U32 },

	[IFLA_GTP_ROLE]			= { .type = NLA_U32 },

};



static int gtp_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -810,6 +820,7 @@ static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) 
{

	struct sock *sk1u = NULL;

	struct sock *sk0 = NULL;

	unsigned int role = GTP_ROLE_GGSN;



	if (data[IFLA_GTP_FD0]) {

		u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]);
@@ -830,8 +841,15 @@ static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) 
		}

	}



	if (data[IFLA_GTP_ROLE]) {

		role = nla_get_u32(data[IFLA_GTP_ROLE]);

		if (role > GTP_ROLE_SGSN)

			return -EINVAL;

	}



	gtp->sk0 = sk0;

	gtp->sk1u = sk1u;

	gtp->role = role;



	return 0;

}

include/uapi/linux/if_link.h

+7 −0
Original line number Diff line number Diff line
@@ -538,11 +538,18 @@ enum { 
#define IFLA_PPP_MAX (__IFLA_PPP_MAX - 1)



/* GTP section */



enum ifla_gtp_role {

	GTP_ROLE_GGSN = 0,

	GTP_ROLE_SGSN,

};



enum {

	IFLA_GTP_UNSPEC,

	IFLA_GTP_FD0,

	IFLA_GTP_FD1,

	IFLA_GTP_PDP_HASHSIZE,

	IFLA_GTP_ROLE,

	__IFLA_GTP_MAX,

};

#define IFLA_GTP_MAX (__IFLA_GTP_MAX - 1)