From 91ed81f9abc76d5a61b07cb8286c680c9330b7a1 Mon Sep 17 00:00:00 2001 From: Jonas Bonn Date: Fri, 24 Mar 2017 23:23:21 +0100 Subject: 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 Acked-by: Pablo Neira Ayuso Acked-by: Harald Welte Signed-off-by: David S. Miller --- drivers/net/gtp.c | 42 ++++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 12 deletions(-) (limited to 'drivers/net/gtp.c') diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 1f6d911e77c7..4fea1b3dfbb4 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; } -- cgit v1.2.3-59-g8ed1b