- Implemented Apache HTTP capture using recvfrom syscall (model identical to nginx)
- Added sys_enter_recvfrom + kretprobe __x64_sys_recvfrom approach
- Renamed Apache BPF maps (apache_http_pid_map, apache_http_recv_args_map) to avoid conflicts with nginx
- Added support for recvfrom and recvmsg syscalls (recvmsg support incomplete)
Test results:
- Rocky 9 (kernel 5.14): nginx HTTP capture works perfectly with full headers
- Rocky 10 (kernel 6.12): Apache HTTP capture NOT working (headers=0)
- CentOS 8 (kernel 4.18): Apache HTTP capture NOT working (headers=0)
Root cause: Apache event MPM uses async epoll model that doesn't trigger
recvfrom syscalls the same way as nginx. Further investigation needed
for Apache-specific capture methods.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Rename apache_pid_map to apache_http_pid_map
- Rename apache_read_args_map to apache_http_recv_args_map
- Update all references in C code and Go loader
- Attempt both tracepoints and kretprobe for Apache HTTP capture
Test results:
- Rocky 9 (kernel 5.14): nginx HTTP capture works perfectly
- Rocky 10 (kernel 6.12): Apache HTTP capture not working (headers=0)
- CentOS 8 (kernel 4.18): Apache HTTP capture not working
The issue appears to be that Apache event MPM may not use recvfrom()
in the same way as nginx, or uses a different code path.
Further investigation needed for Apache HTTP capture.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Add uprobe_apache.c with kretprobe on __x64_sys_recvfrom for Apache HTTP capture
- Update loader.go to support unified "servers" configuration instead of separate nginx_bin_path/apache_enabled
- Add consumeApacheHTTPEvents() function to process Apache HTTP events
- Update bpf_types.h to add Apache-specific BPF maps and structs
- Fix perf event array value_size for pb_apache_http (must be sizeof(__u32) not struct size)
- Add NGINX_APACHE_GUIDE.md documentation for HTTP capture from both servers
Validation results:
- nginx HTTP capture: ✅ Working (57 headers captured, no truncation)
- Apache HTTP capture: ⚠️ Under investigation (kretprobe not triggering on CentOS 8 kernel 4.18)
Configuration:
- JA4EBPF_UPROBES_ENABLED=true
- JA4EBPF_UPROBES_SERVERS=nginx,apache (or "both")
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fixes "permission denied" error when attaching tracepoint sys_exit_recvfrom
on Rocky Linux 9 (kernel 5.14+). The tracepoint exit has stricter permissions
than entry tracepoints.
Changes:
- BPF: SEC("tp/syscalls/sys_exit_recvfrom") → SEC("kretprobe/__x64_sys_recvfrom")
- BPF: Extract retval using PT_REGS_RC(ctx) instead of ctx->ret
- Loader: link.Tracepoint() → link.Kretprobe()
- Add nginxPidMap for filtering recvfrom calls by nginx PID
Validation:
- All HTTP fields captured without truncation (path up to 39 chars, query up to 244 chars)
- Custom headers (X-Request-ID, X-Custom-Header) fully captured
- Unit tests added and passing (TestKretprobeRecvfromAttachment, TestKretprobeVsTracepoint)
- ClickHouse validation complete: http_logs and http_logs_raw tables verified
Tested on:
- Rocky Linux 9 (kernel 5.14+)
- bpftool shows: kprobe name tp_sys_exit_recvfrom (kretprobe active)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add initial implementation of nginx uprobes to capture complete HTTP
headers at application layer. This addresses the limitation of TC-based
capture which truncates headers spanning multiple packets.
Changes:
- Add uprobe_nginx.c with read() syscall interception
- Add nginx_read_args map for uretprobe correlation
- Add AttachUprobesNginx() method with retry support
- Config via uprobes.enabled in YAML or JA4EBPF_UPROBES_ENABLED env var
Current status:
- ✅ HTTPS (TLS) capture works perfectly - complete headers via SSL_read
- ❌ HTTP plain nginx uprobes don't fire - nginx uses recv() not read()
- ⚠️ HTTP plain TC capture truncates headers (fundamental limitation)
Note: The nginx uprobes approach has limitations:
1. nginx uses recv()/recvmsg() syscalls, not read()
2. PLT attachment to glibc recv() doesn't trigger properly
3. Consider kprobes on sys_recvfrom or packet reassembly for future
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fix two critical offset bugs introduced when ip_total_length was added to
tcp_syn_event: tcp_options_raw offset 21→23 and tcp_options_len offset 61→63,
plus minimum size check 70→72. Fix ssl_data_event direction field offset from
4118 (inside timestamp_ns) to 4126. Simplify attachSSLWrite to use generated
objects directly instead of dynamic spec loading. Regenerate BPF objects with
SSL_write uprobe programs included.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add uprobe_ssl_write_entry/uretprobe_ssl_write_exit to capture server HTTP
responses via SSL_write with direction=1. Implement full HPACK decoder
(RFC 7541 static table, multi-byte integers, literal representations) for
HTTP/2 header extraction. Add AcceptCache mapping {tgid,fd}→SessionKey
from accept4 events as authoritative source for SSL correlation when BPF
ssl_conn_map has src_ip=0. Add ip_total_length to tcp_syn_event BPF struct.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Increase MAX_TLS_PAYLOAD from 512 to 2048 bytes to capture full
TLS ClientHellos (modern browsers/curl send 1000-1543 byte ClientHellos)
- Fix ParseClientHello to tolerate XDP-truncated payloads: clamp
recordLength and chLen to available data instead of returning error
- Fix cipher suites, compression, extensions truncation to use clamping
- Fix consumeSynEvents struct field offsets: dst_ip (4 bytes at offset 4)
was not accounted for, causing all L3/L4 metadata to be read from
wrong positions (TTL was actually dst_ip[0], windowSize was dst_port, etc.)
- Add parseTCPOptions() to extract MSS and Window Scale from raw TCP options
(C code sets defaults of mss=0, window_scale=0xFF, expects Go to parse)
- Fix consumeAcceptEvents: skip zero-IP events to avoid phantom sessions
- Fix consumeSSLEvents: filter zero-IP/port events when proc fallback fails
- Add missing consumeHTTPPlainEvents goroutine (was defined but never called)
- Fix race condition: SYN consumer sets Correlated=true if TLS already present
- Update tls_hello_event struct offsets in Go consumer (payload_len now at
offset 2054, was 518, due to payload array growing from 512 to 2048 bytes)
- Remove debug logging from consumers and GC
E2E verified: HTTP plain (port 80) and HTTPS (port 443) both produce
fully correlated sessions in ClickHouse with correct:
- ip_meta_ttl=64, ip_meta_df=true, ip_meta_id
- tcp_meta_window_size=64240, tcp_meta_window_scale=10, tcp_meta_mss=1460
- ja4=t13i3010_1d37bd780c83_95d2a80e6515
- tls_alpn=http/1.1
- method=GET, path=/, header_order_signature=Host;User-Agent;Accept
- correlated=1
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Use two separate //go:generate directives (Ja4Tc for tc_capture.c, Ja4Ssl
for uprobe_ssl.c) to avoid duplicate LICENSE symbol and multi-file clang issue
- Update loader.go to hold tcObjs/sslObjs separately with correct field names:
UprobeSslSetFd, UprobeSslReadEntry, UretprobeSslReadExit,
KprobeAccept4Entry, KretprobeAccept4Exit
- Add systemd-rpm-macros to all three RPM build stages (el8/el9/el10)
so that %{_unitdir} macro resolves correctly
- RPMs now build successfully for el8, el9, el10
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
