mirror of
https://github.com/xdp-project/bpf-examples.git
synced 2024-05-06 15:54:53 +00:00
954c66b0e8
Split and rename files so there is one userspace program (pping) and two kernel-space ones (one for XDP and one for TC-BPF). Copy the shell script for loading the TC-BPF program from traffic-pacing-edt folder, but add support for loading a specific section. The XDP and TC-BPF programs do not share the ts_start map, so program does not work. Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
84 lines
3.0 KiB
C
84 lines
3.0 KiB
C
#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <xdp/parsing_helpers.h>
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#include <linux/in.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/tcp.h>
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#include <string.h>
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#include "pping.h"
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#include "pping_helpers.h"
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char _license[] SEC("license") = "GPL";
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struct bpf_map_def SEC("maps") ts_start = {
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.type = BPF_MAP_TYPE_HASH,
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.key_size = sizeof(struct ts_key),
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.value_size = sizeof(struct ts_timestamp),
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.max_entries = 16384,
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};
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struct bpf_map_def SEC("maps") rtt_events = {
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.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
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.key_size = sizeof(__u32), // CPU ID
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.value_size = sizeof(__u32), // perf file descriptor?
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};
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// XDP program for parsing TSECR-val from ingress traffic and check for match in map
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SEC("pping_ingress")
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int xdp_prog_ingress(struct xdp_md *ctx)
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{
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void *data = (void *)(long)ctx->data;
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void *data_end = (void *)(long)ctx->data_end;
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int proto = -1;
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struct hdr_cursor nh = {.pos = data };
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struct ethhdr *eth;
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struct iphdr *iph;
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struct tcphdr *tcph;
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//bpf_printk("Received packet of length %d\n", (int)(data_end - data));
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proto = parse_ethhdr(&nh, data_end, ð);
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if (bpf_ntohs(proto) != ETH_P_IP)
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goto end; // Not IPv4 packet (or failed to parse ethernet header)
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proto = parse_iphdr(&nh, data_end, &iph);
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if (proto != IPPROTO_TCP)
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goto end; // Not a TCP packet (or failed to parse ethernet header)
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proto = parse_tcphdr(&nh, data_end, &tcph);
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if (proto < 0)
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goto end; // Failed parsing TCP-header
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//bpf_printk("TCP-packet with %d byte header and %lu bytes of data\n", proto, data_end - nh.pos);
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__u32 tsval, tsecr;
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if (parse_tcp_ts(tcph, data_end, &tsval, &tsecr) < 0) // No TCP timestamp
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goto end;
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// We have a TCP-timestamp - now we can check if it's in the map
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//bpf_printk("TCP-packet with timestap. TSval: %u, TSecr: %u\n", bpf_ntohl(tsval), bpf_ntohl(tsecr));
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struct ts_key key;
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fill_ipv4_flow(&(key.flow), iph->daddr, iph->saddr, tcph->dest, tcph->source); // Fill in reverse order of egress (dest <--> source)
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key.tsval = tsecr;
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// Should only look up map map (filling done on egress), but temporarily add to map before I get the TC-BPF part working
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struct ts_timestamp wrong_value = {0};
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wrong_value.timestamp = bpf_ktime_get_ns(); //Verifier was unhappy when using bpf_ktime_get_boot_ns
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bpf_map_update_elem(&ts_start, &key, &wrong_value, BPF_NOEXIST);
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struct ts_timestamp *ts = bpf_map_lookup_elem(&ts_start, &key);
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if (ts && ts->used == 0) { // Only calculate RTT for first packet with matching TSecr
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// As used is not set atomically with the lookup, could potentially have multiple "first" packets (on different CPUs), but all those should then also have very similar RTT, so don't consider it a significant issue
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ts->used = 1;
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struct rtt_event event = {0};
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memcpy(&(event.flow), &(key.flow), sizeof(struct ipv4_flow));
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event.rtt = bpf_ktime_get_ns() - ts->timestamp;
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bpf_perf_event_output(ctx, &rtt_events, BPF_F_CURRENT_CPU, &event, sizeof(event));
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bpf_printk("Pushed rtt event with RTT: %llu\n", event.rtt);
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}
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end:
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return XDP_PASS;
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}
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