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Message-Id: <20170324222321.28618-3-jonas@southpole.se>
Date: Fri, 24 Mar 2017 23:23:21 +0100
From: Jonas Bonn <jonas@...thpole.se>
To: pablo@...filter.org, netdev@...r.kernel.org, laforge@...monks.org
Cc: Jonas Bonn <jonas@...thpole.se>
Subject: [PATCH net-next v5 2/2] 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: Jonas Bonn <jonas@...thpole.se>
Acked-by: Pablo Neira Ayuso <pablo@...filter.org>
Acked-by: Harald Welte <laforge@...monks.org>
---
drivers/net/gtp.c | 42 ++++++++++++++++++++++++++++++------------
include/uapi/linux/if_link.h | 7 +++++++
2 files changed, 37 insertions(+), 12 deletions(-)
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 1f6d911..4fea1b3 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -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);
- return iph->saddr == pctx->ms_addr_ip4.s_addr;
+ 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);
- pctx = ipv4_pdp_find(gtp, iph->daddr);
+ 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;
}
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 320fc1e..8b405af 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -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)
--
2.9.3
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