diff options
Diffstat (limited to '')
| -rw-r--r-- | xdp-dump/xdpdump_bpf.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/xdp-dump/xdpdump_bpf.c b/xdp-dump/xdpdump_bpf.c new file mode 100644 index 0000000..7161b30 --- /dev/null +++ b/xdp-dump/xdpdump_bpf.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 + +/***************************************************************************** + * Include files + *****************************************************************************/ +#include <stdbool.h> +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_trace_helpers.h> +#include "xdpdump.h" + +/***************************************************************************** + * Macros + *****************************************************************************/ +#define min(x,y) ((x)<(y) ? x : y) + +/***************************************************************************** + * (re)definition of kernel data structures for use with BTF + *****************************************************************************/ +struct net_device { + /* Structure does not need to contain all entries, + * as "preserve_access_index" will use BTF to fix this... + */ + int ifindex; +} __attribute__((preserve_access_index)); + +struct xdp_rxq_info { + /* Structure does not need to contain all entries, + * as "preserve_access_index" will use BTF to fix this... + */ + struct net_device *dev; + __u32 queue_index; +} __attribute__((preserve_access_index)); + +struct xdp_buff { + void *data; + void *data_end; + void *data_meta; + void *data_hard_start; + unsigned long handle; + struct xdp_rxq_info *rxq; +} __attribute__((preserve_access_index)); + +/***************************************************************************** + * Local definitions and global variables + *****************************************************************************/ +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(max_entries, MAX_CPUS); + __type(key, int); + __type(value, __u32); +} xdpdump_perf_map SEC(".maps"); + + +/***************************************************************************** + * .data section value storing the capture configuration + *****************************************************************************/ +struct trace_configuration trace_cfg SEC(".data"); + +/***************************************************************************** + * trace_to_perf_buffer() + *****************************************************************************/ +static inline void trace_to_perf_buffer(struct xdp_buff *xdp, bool fexit, + int action) +{ + void *data_end = (void *)(long)xdp->data_end; + void *data = (void *)(long)xdp->data; + struct pkt_trace_metadata metadata; + + if (data >= data_end || + trace_cfg.capture_if_ifindex != xdp->rxq->dev->ifindex) + return; + + metadata.prog_index = trace_cfg.capture_prog_index; + metadata.ifindex = xdp->rxq->dev->ifindex; + metadata.rx_queue = xdp->rxq->queue_index; + metadata.pkt_len = (__u16)(data_end - data); + metadata.cap_len = min(metadata.pkt_len, trace_cfg.capture_snaplen); + metadata.action = action; + metadata.flags = 0; + + if (fexit) + metadata.flags |= MDF_DIRECTION_FEXIT; + + bpf_xdp_output(xdp, &xdpdump_perf_map, + ((__u64) metadata.cap_len << 32) | + BPF_F_CURRENT_CPU, + &metadata, sizeof(metadata)); +} + +/***************************************************************************** + * trace_on_entry() + *****************************************************************************/ +SEC("fentry/func") +int BPF_PROG(trace_on_entry, struct xdp_buff *xdp) +{ + trace_to_perf_buffer(xdp, false, 0); + return 0; +} + +/***************************************************************************** + * trace_on_exit() + *****************************************************************************/ +SEC("fexit/func") +int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret) +{ + trace_to_perf_buffer(xdp, true, ret); + return 0; +} + +/***************************************************************************** + * License + *****************************************************************************/ +char _license[] SEC("license") = "GPL"; |