NobinPegasus
Member
I've completed the assignment as mentioned in the solutions.
Here's the repo I'm trying to test on my local machine:
github.com
Here's my C code:
Command used to compile and run this program:
Why am I facing this error? How can I fix it?
Here's the repo I'm trying to test on my local machine:
xdp-tutorial/packet01-parsing/README.org at master · xdp-project/xdp-tutorial
XDP tutorial. Contribute to xdp-project/xdp-tutorial development by creating an account on GitHub.
github.com
Here's my C code:
Code:
/* SPDX-License-Identifier: GPL-2.0 */
#include <stddef.h>
#include <linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
/* Defines xdp_stats_map from packet04 */
#include "../common/xdp_stats_kern_user.h"
#include "../common/xdp_stats_kern.h"
/* Header cursor to keep track of current parsing position */
/* Packet parsing helpers.
*
* Each helper parses a packet header, including doing bounds checking, and
* returns the type of its contents if successful, and -1 otherwise.
*
* For Ethernet and IP headers, the content type is the type of the payload
* (h_proto for Ethernet, nexthdr for IPv6), for ICMP it is the ICMP type field.
* All return values are in host byte order.
*/
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/udp.h>
#include <linux/tcp.h>
/* Header cursor to keep track of current parsing position */
struct hdr_cursor {
void *pos;
};
/*
* struct vlan_hdr - vlan header
* @h_vlan_TCI: priority and VLAN ID
* @h_vlan_encapsulated_proto: packet type ID or len
*/
struct vlan_hdr {
__be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto;
};
/*
* Struct icmphdr_common represents the common part of the icmphdr and icmp6hdr
* structures.
*/
struct icmphdr_common {
__u8 type;
__u8 code;
__sum16 cksum;
};
/* Allow users of header file to redefine VLAN max depth */
#ifndef VLAN_MAX_DEPTH
#define VLAN_MAX_DEPTH 2
#endif
#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
/* Struct for collecting VLANs after parsing via parse_ethhdr_vlan */
struct collect_vlans {
__u16 id[VLAN_MAX_DEPTH];
};
static __always_inline int proto_is_vlan(__u16 h_proto)
{
return !!(h_proto == bpf_htons(ETH_P_8021Q) ||
h_proto == bpf_htons(ETH_P_8021AD));
}
/* Notice, parse_ethhdr() will skip VLAN tags, by advancing nh->pos and returns
* next header EtherType, BUT the ethhdr pointer supplied still points to the
* 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_vlan(struct hdr_cursor *nh,
void *data_end,
struct ethhdr **ethhdr,
struct collect_vlans *vlans)
{
struct ethhdr *eth = nh->pos;
int hdrsize = sizeof(*eth);
struct vlan_hdr *vlh;
__u16 h_proto;
int i;
/* Byte-count bounds check; check if current pointer + size of header
* is after data_end.
*/
if (nh->pos + hdrsize > data_end)
return -1;
nh->pos += hdrsize;
*ethhdr = eth;
vlh = nh->pos;
h_proto = eth->h_proto;
/* Use loop unrolling to avoid the verifier restriction on loops;
* support up to VLAN_MAX_DEPTH layers of VLAN encapsulation.
*/
#pragma unroll
for (i = 0; i < VLAN_MAX_DEPTH; i++) {
if (!proto_is_vlan(h_proto))
break;
if (vlh + 1 > 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 removes the code that collects 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)
// {
// struct ipv6hdr *ip6h = nh->pos;
// /* Pointer-arithmetic bounds check; pointer +1 points to after end of
// * thing being pointed to. We will be using this style in the remainder
// * of the tutorial.
// */
// if (ip6h + 1 > data_end)
// return -1;
// nh->pos = ip6h + 1;
// *ip6hdr = ip6h;
// return ip6h->nexthdr;
// }
static __always_inline int parse_iphdr(struct hdr_cursor *nh,
void *data_end,
struct iphdr **iphdr)
{
struct iphdr *iph = nh->pos;
int hdrsize;
if (iph + 1 > data_end)
return -1;
hdrsize = iph->ihl * 4;
/* Sanity check packet field is valid */
if(hdrsize < sizeof(*iph))
return -1;
/* Variable-length IPv4 header, need to use byte-based arithmetic */
if (nh->pos + hdrsize > data_end)
return -1;
nh->pos += hdrsize;
*iphdr = iph;
return iph->protocol;
}
// static __always_inline int parse_icmp6hdr(struct hdr_cursor *nh,
// void *data_end,
// struct icmp6hdr **icmp6hdr)
// {
// struct icmp6hdr *icmp6h = nh->pos;
// if (icmp6h + 1 > data_end)
// return -1;
// nh->pos = icmp6h + 1;
// *icmp6hdr = icmp6h;
// return icmp6h->icmp6_type;
// }
static __always_inline int parse_icmphdr(struct hdr_cursor *nh,
void *data_end,
struct icmphdr **icmphdr)
{
struct icmphdr *icmph = nh->pos;
if (icmph + 1 > data_end)
return -1;
nh->pos = icmph + 1;
*icmphdr = icmph;
return icmph->type;
}
// static __always_inline int parse_icmphdr_common(struct hdr_cursor *nh,
// void *data_end,
// struct icmphdr_common **icmphdr)
// {
// struct icmphdr_common *h = nh->pos;
// if (h + 1 > data_end)
// return -1;
// nh->pos = h + 1;
// *icmphdr = h;
// return h->type;
// }
/*
* parse_udphdr: parse the udp header and return the length of the udp payload
*/
// static __always_inline int parse_udphdr(struct hdr_cursor *nh,
// void *data_end,
// struct udphdr **udphdr)
// {
// int len;
// struct udphdr *h = nh->pos;
// if (h + 1 > data_end)
// return -1;
// nh->pos = h + 1;
// *udphdr = h;
// len = bpf_ntohs(h->len) - sizeof(struct udphdr);
// if (len < 0)
// return -1;
// return len;
// }
/*
* parse_tcphdr: parse and return the length of the tcp header
*/
// static __always_inline int parse_tcphdr(struct hdr_cursor *nh,
// void *data_end,
// struct tcphdr **tcphdr)
// {
// int len;
// struct tcphdr *h = nh->pos;
// if (h + 1 > data_end)
// return -1;
// len = h->doff * 4;
// /* Sanity check packet field is valid */
// if(len < sizeof(*h))
// return -1;
// /* Variable-length TCP header, need to use byte-based arithmetic */
// if (nh->pos + len > data_end)
// return -1;
// nh->pos += len;
// *tcphdr = h;
// return len;
// }
// static __always_inline __u16 my_ntohs(__u16 netshort) {
// return ((netshort & 0xFF00) >> 8) | ((netshort & 0x00FF) << 8);
// }
SEC("xdp")
int xdp_parser_func(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth;
/* Default action XDP_PASS, imply everything we couldn't parse, or that
* we don't want to deal with, we just pass up the stack and let the
* kernel deal with it.
*/
__u32 action = XDP_PASS; /* Default action */
/* These keep track of the next header type and iterator pointer */
struct hdr_cursor nh;
int nh_type;
/* Start next header cursor position at data start */
nh.pos = data;
/* Packet parsing in steps: Get each header one at a time, aborting if
* parsing fails. Each helper function does sanity checking (is the
* header type in the packet correct?), and bounds checking.
*/
nh_type = parse_ethhdr(&nh, data_end, ð);
if (nh_type == bpf_htons(ETH_P_8021Q)) {
struct collect_vlans vlans;
int vlan_proto = parse_ethhdr_vlan(&nh, data_end, ð, &vlans);
if (vlan_proto < 0)
goto out;
// Print VLAN information
for (int i = 0; i < VLAN_MAX_DEPTH; i++) {
if (vlans.id[i] == 0)
break;
bpf_trace_printk("VLAN ID[%d] = %u\n", i, vlans.id[i]);
}
}
// Proceed to IPv4 or IPv6 parsing
// if (nh_type == bpf_htons(ETH_P_IPV6)) {
// struct ipv6hdr *ip6hdr;
// int ip6_next_header = parse_ip6hdr(&nh, data_end, &ip6hdr);
// if (ip6_next_header == IPPROTO_ICMPV6) {
// struct icmp6hdr *icmp6hdr;
// int icmp6_type = parse_icmp6hdr(&nh, data_end, &icmp6hdr);
// if (icmp6_type < 0)
// goto out;
// // Print IPv6 header information
// bpf_trace_printk("IPv6 Header: Source Address = %x:%x:%x:%x:%x:%x:%x:%x, Destination Address = %x:%x:%x:%x:%x:%x:%x:%x\n",
// my_ntohs(ip6hdr->saddr.s6_addr16[0]), my_ntohs(ip6hdr->saddr.s6_addr16[1]),
// my_ntohs(ip6hdr->saddr.s6_addr16[2]), my_ntohs(ip6hdr->saddr.s6_addr16[3]),
// my_ntohs(ip6hdr->saddr.s6_addr16[4]), my_ntohs(ip6hdr->saddr.s6_addr16[5]),
// my_ntohs(ip6hdr->saddr.s6_addr16[6]), my_ntohs(ip6hdr->saddr.s6_addr16[7]),
// my_ntohs(ip6hdr->daddr.s6_addr16[0]), my_ntohs(ip6hdr->daddr.s6_addr16[1]),
// my_ntohs(ip6hdr->daddr.s6_addr16[2]), my_ntohs(ip6hdr->daddr.s6_addr16[3]),
// my_ntohs(ip6hdr->daddr.s6_addr16[4]), my_ntohs(ip6hdr->daddr.s6_addr16[5]),
// my_ntohs(ip6hdr->daddr.s6_addr16[6]), my_ntohs(ip6hdr->daddr.s6_addr16[7]));
// bpf_trace_printk("Next Header = %d\n", ip6hdr->nexthdr);
// // Print ICMPv6 header information
// bpf_trace_printk("ICMPv6 Header: Type = %d, Code = %d\n",
// icmp6hdr->icmp6_type, icmp6hdr->icmp6_code);
// }
// }
if (nh_type == bpf_htons(ETH_P_IP)) {
struct iphdr *iphdr;
int ip_next_header = parse_iphdr(&nh, data_end, &iphdr);
if (ip_next_header == IPPROTO_ICMP) {
struct icmphdr *icmphdr;
int icmp_type = parse_icmphdr(&nh, data_end, &icmphdr);
if (icmp_type < 0)
goto out;
// Print IPv4 header information
bpf_trace_printk("IPv4 Header: Source Address = %x, Destination Address = %x\n",
bpf_ntohl(iphdr->saddr), bpf_ntohl(iphdr->daddr));
bpf_trace_printk("Protocol = %d\n", iphdr->protocol);
// Print ICMP header information
bpf_trace_printk("ICMP Header: Type = %d, Code = %d\n",
icmphdr->type, icmphdr->code);
}
}
// Add more parsing or processing for IPv6, ICMPv6, VLAN, IPv4, and ICMP headers here if needed
// Set action based on parsed headers
// For example, drop packets with certain conditions
// action = XDP_DROP;
out:
return xdp_stats_record_action(ctx, action); /* read via xdp_stats */
}
char _license[] SEC("license") = "GPL";
Code:
cd packet01-parsing
make
sudo ip link set dev test xdpgeneric obj xdp_prog_kern.o sec xdp
Code:
pegasus@pegasus:~/Documents/xdp-tutorial/packet01-parsing$ sudo ip link set dev test xdpgeneric obj xdp_prog_kern.o sec xdp
[sudo] password for pegasus:
libbpf: prog 'xdp_parser_func': BPF program load failed: Permission denied
libbpf: prog 'xdp_parser_func': -- BEGIN PROG LOAD LOG --
0: R1=ctx(off=0,imm=0) R10=fp0
; int xdp_parser_func(struct xdp_md *ctx)
0: (bf) r6 = r1 ; R1=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0)
; void *data_end = (void *)(long)ctx->data_end;
1: (61) r1 = *(u32 *)(r6 +4) ; R1_w=pkt_end(off=0,imm=0) R6_w=ctx(off=0,imm=0)
; void *data = (void *)(long)ctx->data;
2: (61) r3 = *(u32 *)(r6 +0) ; R3_w=pkt(off=0,r=0,imm=0) R6_w=ctx(off=0,imm=0)
; if (nh->pos + hdrsize > data_end)
3: (bf) r8 = r3 ; R3_w=pkt(off=0,r=0,imm=0) R8_w=pkt(off=0,r=0,imm=0)
4: (07) r8 += 14 ; R8_w=pkt(off=14,r=0,imm=0)
; if (nh->pos + hdrsize > data_end)
5: (2d) if r8 > r1 goto pc+73 ; R1_w=pkt_end(off=0,imm=0) R8_w=pkt(off=14,r=14,imm=0)
;
6: (71) r4 = *(u8 *)(r3 +12) ; R3_w=pkt(off=0,r=14,imm=0) R4_w=scalar(umax=255,var_off=(0x0; 0xff))
7: (71) r2 = *(u8 *)(r3 +13) ; R2_w=scalar(umax=255,var_off=(0x0; 0xff)) R3_w=pkt(off=0,r=14,imm=0)
8: (67) r2 <<= 8 ; R2_w=scalar(umax=65280,var_off=(0x0; 0xff00))
9: (4f) r2 |= r4 ; R2_w=scalar() R4_w=scalar(umax=255,var_off=(0x0; 0xff))
; if (!proto_is_vlan(h_proto))
10: (15) if r2 == 0xa888 goto pc+1 ; R2_w=scalar()
11: (55) if r2 != 0x81 goto pc+19 ; R2=129
; if (vlh + 1 > data_end)
12: (bf) r4 = r3 ; R3=pkt(off=0,r=14,imm=0) R4_w=pkt(off=0,r=14,imm=0)
13: (07) r4 += 18 ; R4_w=pkt(off=18,r=14,imm=0)
; if (vlh + 1 > data_end)
14: (2d) if r4 > r1 goto pc+16 ; R1=pkt_end(off=0,imm=0) R4_w=pkt(off=18,r=18,imm=0)
;
15: (71) r5 = *(u8 *)(r3 +16) ; R3=pkt(off=0,r=18,imm=0) R5_w=scalar(umax=255,var_off=(0x0; 0xff))
16: (71) r2 = *(u8 *)(r3 +17) ; R2_w=scalar(umax=255,var_off=(0x0; 0xff)) R3=pkt(off=0,r=18,imm=0)
17: (67) r2 <<= 8 ; R2_w=scalar(umax=65280,var_off=(0x0; 0xff00))
18: (4f) r2 |= r5 ; R2=scalar() R5=scalar(umax=255,var_off=(0x0; 0xff))
; if (!proto_is_vlan(h_proto))
19: (15) if r2 == 0xa888 goto pc+2 ; R2=scalar()
20: (bf) r8 = r4 ; R4=pkt(off=18,r=18,imm=0) R8_w=pkt(off=18,r=18,imm=0)
21: (55) if r2 != 0x81 goto pc+9 ; R2=129
; if (vlh + 1 > data_end)
22: (bf) r5 = r3 ; R3=pkt(off=0,r=18,imm=0) R5_w=pkt(off=0,r=18,imm=0)
23: (07) r5 += 22 ; R5_w=pkt(off=22,r=18,imm=0)
24: (bf) r8 = r4 ; R4=pkt(off=18,r=18,imm=0) R8_w=pkt(off=18,r=18,imm=0)
; if (vlh + 1 > data_end)
25: (2d) if r5 > r1 goto pc+5 ; R1=pkt_end(off=0,imm=0) R5_w=pkt(off=22,r=22,imm=0)
;
26: (71) r4 = *(u8 *)(r3 +20) ; R3=pkt(off=0,r=22,imm=0) R4_w=scalar(umax=255,var_off=(0x0; 0xff))
27: (71) r2 = *(u8 *)(r3 +21) ; R2_w=scalar(umax=255,var_off=(0x0; 0xff)) R3=pkt(off=0,r=22,imm=0)
28: (67) r2 <<= 8 ; R2_w=scalar(umax=65280,var_off=(0x0; 0xff00))
29: (4f) r2 |= r4 ; R2_w=scalar() R4_w=scalar(umax=255,var_off=(0x0; 0xff))
30: (bf) r8 = r5 ; R5=pkt(off=22,r=22,imm=0) R8=pkt(off=22,r=22,imm=0)
; if (nh_type == bpf_htons(ETH_P_8021Q)) {
31: (15) if r2 == 0x8 goto pc+70 ; R2=scalar()
32: (55) if r2 != 0x81 goto pc+46 ; R2=129
; if (nh->pos + hdrsize > data_end)
33: (bf) r2 = r8 ; R2_w=pkt(off=22,r=22,imm=0) R8=pkt(off=22,r=22,imm=0)
34: (07) r2 += 14 ; R2_w=pkt(off=36,r=22,imm=0)
; if (nh->pos + hdrsize > data_end)
35: (2d) if r2 > r1 goto pc+43 ; R1=pkt_end(off=0,imm=0) R2_w=pkt(off=36,r=36,imm=0)
; h_proto = eth->h_proto;
36: (71) r3 = *(u8 *)(r8 +12) ; R3_w=scalar(umax=255,var_off=(0x0; 0xff)) R8=pkt(off=22,r=36,imm=0)
37: (71) r2 = *(u8 *)(r8 +13) ; R2_w=scalar(umax=255,var_off=(0x0; 0xff)) R8=pkt(off=22,r=36,imm=0)
38: (67) r2 <<= 8 ; R2_w=scalar(umax=65280,var_off=(0x0; 0xff00))
39: (4f) r2 |= r3 ; R2=scalar() R3=scalar(umax=255,var_off=(0x0; 0xff))
; if (!proto_is_vlan(h_proto))
40: (15) if r2 == 0xa888 goto pc+1 ; R2=scalar()
41: (55) if r2 != 0x81 goto pc+92 ; R2=129
; if (vlh + 1 > data_end)
42: (bf) r2 = r8 ; R2_w=pkt(off=22,r=36,imm=0) R8=pkt(off=22,r=36,imm=0)
43: (07) r2 += 18 ; R2_w=pkt(off=40,r=36,imm=0)
; if (vlh + 1 > data_end)
44: (2d) if r2 > r1 goto pc+89 ; R1=pkt_end(off=0,imm=0) R2_w=pkt(off=40,r=40,imm=0)
; h_proto = vlh->h_vlan_encapsulated_proto;
45: (69) r5 = *(u16 *)(r8 +16) ; R5_w=scalar(umax=65535,var_off=(0x0; 0xffff)) R8=pkt(off=22,r=40,imm=0)
46: (b7) r4 = 1 ; R4_w=1
47: (b7) r3 = 1 ; R3=1
; return !!(h_proto == bpf_htons(ETH_P_8021Q) ||
48: (55) if r5 != 0x81 goto pc+1 ; R5=129
49: (b7) r3 = 0 ; R3_w=0
; return !!(h_proto == bpf_htons(ETH_P_8021Q) ||
50: (55) if r5 != 0xa888 goto pc+1 ; R5=129
; if (!proto_is_vlan(h_proto))
52: (5f) r4 &= r3 ; R3_w=0 R4_w=0
; (bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK);
53: (69) r3 = *(u16 *)(r8 +14) ; R3_w=scalar(umax=65535,var_off=(0x0; 0xffff)) R8=pkt(off=22,r=40,imm=0)
; (bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK);
54: (57) r3 &= -241 ; R3_w=scalar(umax=65295,var_off=(0x0; 0xff0f))
; if (!proto_is_vlan(h_proto))
55: (57) r4 &= 1 ; R4_w=0
56: (55) if r4 != 0x0 goto pc+5 ; R4_w=0
57: (07) r8 += 22 ; R8=pkt(off=44,r=40,imm=0)
58: (2d) if r8 > r1 goto pc+3 ; R1=pkt_end(off=0,imm=0) R8=pkt(off=44,r=44,imm=0)
; (bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK);
59: (69) r7 = *(u16 *)(r2 +0) ; R2=pkt(off=40,r=44,imm=0) R7_w=scalar(umax=65535,var_off=(0x0; 0xffff))
; (bpf_ntohs(vlh->h_vlan_TCI) & VLAN_VID_MASK);
60: (57) r7 &= 65295 ; R7_w=scalar(umax=65295,var_off=(0x0; 0xff0f))
61: (dc) r7 = be16 r7 ; R7_w=scalar()
; if (vlans.id[i] == 0)
62: (bf) r1 = r3 ; R1_w=scalar(id=1,umax=65295,var_off=(0x0; 0xff0f)) R3=scalar(id=1,umax=65295,var_off=(0x0; 0xff0f))
63: (57) r1 &= 65535 ; R1_w=scalar(umax=65295,var_off=(0x0; 0xff0f))
; if (vlans.id[i] == 0)
64: (15) if r1 == 0x0 goto pc+14 ; R1_w=scalar(umax=65295,var_off=(0x0; 0xff0f))
;
65: (dc) r3 = be16 r3 ; R3_w=scalar()
; bpf_trace_printk("VLAN ID[%d] = %u\n", i, vlans.id[i]);
66: (18) r1 = 0xffff948a54165510 ; R1_w=map_value(off=0,ks=4,vs=128,imm=0)
68: (b7) r2 = 0 ; R2_w=0
69: (85) call bpf_trace_printk#6
invalid access to map value, value_size=128 off=0 size=0
R1 min value is outside of the allowed memory range
processed 68 insns (limit 1000000) max_states_per_insn 0 total_states 6 peak_states 6 mark_read 2
-- END PROG LOAD LOG --
libbpf: prog 'xdp_parser_func': failed to load: -13
libbpf: failed to load object 'xdp_prog_kern.o'
