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Tutorial planned improvements to parsing #73

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Tutorial planned improvements to parsing #73

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f6e2e65
common: parsing_headers.h reduce default VLAN depth to 2
netoptimizer Sep 3, 2019
3d4bd92
packet-solutionsi xdp_vlan02_kern VLAN extraction missed bpf_ntohs()
netoptimizer Sep 3, 2019
c2b44a2
Create parse_ethhdr_vlan() in parsing_helpers.h
netoptimizer Sep 3, 2019
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25 changes: 22 additions & 3 deletions common/parsing_helpers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,9 +56,14 @@ struct icmphdr_common {

/* Allow users of header file to redefine VLAN max depth */
#ifndef VLAN_MAX_DEPTH
#define VLAN_MAX_DEPTH 4
#define VLAN_MAX_DEPTH 2
#endif

#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
struct vlans {
__u16 id[VLAN_MAX_DEPTH];
};

static __always_inline int proto_is_vlan(__u16 h_proto)
{
return !!(h_proto == bpf_htons(ETH_P_8021Q) ||
Expand All @@ -70,8 +75,10 @@ static __always_inline int proto_is_vlan(__u16 h_proto)
* Ethernet header. Thus, caller can look at eth->h_proto to see if this was a
* VLAN tagged packet.
*/
static __always_inline int parse_ethhdr(struct hdr_cursor *nh, void *data_end,
struct ethhdr **ethhdr)
static __always_inline int parse_ethhdr_vlan(struct hdr_cursor *nh,
void *data_end,
struct ethhdr **ethhdr,
struct vlans *vlans)
{
struct ethhdr *eth = nh->pos;
int hdrsize = sizeof(*eth);
Expand Down Expand Up @@ -102,13 +109,25 @@ static __always_inline int parse_ethhdr(struct hdr_cursor *nh, void *data_end,
break;

h_proto = vlh->h_vlan_encapsulated_proto;
if (vlans) /* collect VLAN ids */
vlans->id[i] =
(bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK);

vlh++;
}

nh->pos = vlh;
return h_proto; /* network-byte-order */
}

static __always_inline int parse_ethhdr(struct hdr_cursor *nh,
void *data_end,
struct ethhdr **ethhdr)
{
/* Expect compiler to remove collect VLAN ids */
return parse_ethhdr_vlan(nh, data_end, ethhdr, NULL);
}

static __always_inline int parse_ip6hdr(struct hdr_cursor *nh,
void *data_end,
struct ipv6hdr **ip6hdr)
Expand Down
2 changes: 1 addition & 1 deletion libbpf
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Submodule libbpf updated 34 files
+4 −35 .travis.yml
+0 −1 BPF-CHECKPOINT-COMMIT
+1 −1 CHECKPOINT-COMMIT
+62 −0 README
+0 −70 README.md
+0 −5 include/linux/err.h
+6 −19 include/linux/filter.h
+75 −240 include/uapi/linux/bpf.h
+1 −1 include/uapi/linux/btf.h
+0 −6 include/uapi/linux/if_link.h
+0 −21 include/uapi/linux/if_xdp.h
+96 −242 scripts/sync-kernel.sh
+0 −2 src/.gitignore
+11 −11 src/Makefile
+1 −2 src/README.rst
+17 −17 src/bpf.c
+1 −4 src/bpf.h
+4 −1 src/bpf_prog_linfo.c
+260 −325 src/btf.c
+0 −202 src/btf.h
+0 −1,287 src/btf_dump.c
+0 −229 src/hashmap.c
+0 −178 src/hashmap.h
+422 −2,740 src/libbpf.c
+32 −126 src/libbpf.h
+0 −25 src/libbpf.map
+0 −154 src/libbpf_internal.h
+1 −80 src/libbpf_probes.c
+14 −1 src/libbpf_util.h
+1 −1 src/str_error.c
+158 −111 src/xsk.c
+1 −7 src/xsk.h
+15 −31 travis-ci/managers/debian.sh
+1 −3 travis-ci/managers/xenial.sh
9 changes: 7 additions & 2 deletions packet-solutions/xdp_vlan02_kern.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,11 +10,14 @@
#define VLAN_MAX_DEPTH 10
#include "../common/parsing_helpers.h"

#if 0
#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
struct vlans {
__u16 id[VLAN_MAX_DEPTH];
};
#endif

#if 0 /* moved to parsing_helpers.h */
/* Based on parse_ethhdr() */
static __always_inline int __parse_ethhdr_vlan(struct hdr_cursor *nh,
void *data_end,
Expand Down Expand Up @@ -51,14 +54,16 @@ static __always_inline int __parse_ethhdr_vlan(struct hdr_cursor *nh,

h_proto = vlh->h_vlan_encapsulated_proto;
if (vlans) {
vlans->id[i] = vlh->h_vlan_TCI & VLAN_VID_MASK;
vlans->id[i] =
bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK;
}
vlh++;
}

nh->pos = vlh;
return h_proto; /* network-byte-order */
}
#endif

SEC("xdp_vlan02")
int xdp_vlan_02(struct xdp_md *ctx)
Expand All @@ -74,7 +79,7 @@ int xdp_vlan_02(struct xdp_md *ctx)
struct vlans vlans;

struct ethhdr *eth;
eth_type = __parse_ethhdr_vlan(&nh, data_end, &eth, &vlans);
eth_type = parse_ethhdr_vlan(&nh, data_end, &eth, &vlans);

if (eth_type < 0)
return XDP_ABORTED;
Expand Down