diff options
| author | Pablo Neira Ayuso <pablo@gnumonks.org> | 2014-03-18 17:27:32 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@gnumonks.org> | 2014-03-18 18:30:05 +0100 |
| commit | 2cbf0a14830ef97ed97a61da4d669c0be03f5ddb (patch) | |
| tree | da27a1550d6c2b9e2b4b7273e8ddb7fa616304c2 | |
| parent | 151652cc809a57f3ef57654ad3cba0c1f006b109 (diff) | |
gtp: fix wrong handling of option header fields in GTPv1
TS 29.060 expresses thing is a quite complicated way just to say
that if any of the optional fields is there, then all optional
fields become mandatory :-).
"This field shall be present if and only if any one or more of the S,
PN and E flags are set.".
So, if any flag is set, we *always* have 4 extra bytes.
| -rw-r--r-- | gtp.c | 21 |
1 files changed, 8 insertions, 13 deletions
@@ -260,17 +260,6 @@ out_rcu: return ret; } -static u8 gtp1u_header_len[] = { - [0] = 0, /* 0 */ - [GTP1_F_SEQ] = 2, /* 2 */ - [GTP1_F_NPDU] = 1, /* 1 */ - [GTP1_F_SEQ|GTP1_F_NPDU] = 3, /* 2 + 1 */ - [GTP1_F_EXTHDR] = 1, /* 1 */ - [GTP1_F_EXTHDR|GTP1_F_SEQ] = 3, /* 1 + 2 */ - [GTP1_F_EXTHDR|GTP1_F_NPDU] = 2, /* 1 + 1 */ - [GTP1_F_EXTHDR|GTP1_F_NPDU|GTP1_F_SEQ] = 4, /* 1 + 1 + 2 */ -}; - static int gtp1u_udp_encap_recv(struct gtp_instance *gti, struct sk_buff *skb) { struct gtp1_header *gtp1; @@ -294,8 +283,14 @@ static int gtp1u_udp_encap_recv(struct gtp_instance *gti, struct sk_buff *skb) if (gtp1->type != GTP_TPDU) return 1; - /* look-up table for faster length computing */ - hdrlen += gtp1u_header_len[gtp1->flags & GTP1_F_MASK]; + /* From 29.060: "This field shall be present if and only if any one or + * more of the S, PN and E flags are set.". + * + * If any of the bit is set, then the remaining ones also have to be + * set. + */ + if (gtp1->flags & GTP1_F_MASK) + hdrlen += 4; /* check for sufficient header size for extension */ if (!pskb_may_pull(skb, hdrlen)) |