[PATCH 1/2 openggsn] gtp: fix wrong binary layout for struct gtp0_header in x86_64

From: Pablo Neira Ayuso <pablo(a)gnumonks.org> struct gtp0_header needs __attribute__((packed)) to make sure that gcc doesn't add a hole of 4 bytes to align the 64-bits teid, resulting in 24 bytes instead of 20 bytes. This was breaking gtpv0 in my gprs testbed with my x86_64 laptop. While at it, add also attribute packed to other headers just to make sure that gcc doesn't pad the structures with holes. --- If no objections, I'll push this to master. gtp/gtp.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/gtp/gtp.h b/gtp/gtp.h index 54af96e..39a902f 100644 --- a/gtp/gtp.h +++ b/gtp/gtp.h @@ -161,7 +161,7 @@ struct gtp0_header { /* Descriptions from 3GPP 09.60 */ uint8_t spare2; /* 11 Spare */ uint8_t spare3; /* 12 Spare */ uint64_t tid; /* 13 Tunnel ID */ -}; /* 20 */ +} __attribute__((packed)); /* 20 */ struct gtp1_header_short { /* Descriptions from 3GPP 29060 */ uint8_t flags; /* 01 bitfield, with typical values */ @@ -174,7 +174,7 @@ struct gtp1_header_short { /* Descriptions from 3GPP 29060 */ uint8_t type; /* 02 Message type. T-PDU = 0xff */ uint16_t length; /* 03 Length (of IP packet or signalling) */ uint32_t tei; /* 05 - 08 Tunnel Endpoint ID */ -}; +} __attribute__((packed)); struct gtp1_header_long { /* Descriptions from 3GPP 29060 */ uint8_t flags; /* 01 bitfield, with typical values */ @@ -190,7 +190,7 @@ struct gtp1_header_long { /* Descriptions from 3GPP 29060 */ uint16_t seq; /* 10 Sequence Number */ uint8_t npdu; /* 11 N-PDU Number */ uint8_t next; /* 12 Next extension header type. Empty = 0 */ -}; +} __attribute__((packed)); struct gtp0_packet { struct gtp0_header h; -- 1.7.10.4