irmd: Add build option to log OAP header info

This adds a DEBUG_PROTO_OAP option to show some information in the OAP
headers received by the IRMd during flow allocation.

Example for unencrypted flow (send):

  OAP_HDR [528b7bf81df8e9bc @ 2025-08-05 17:05:29 (UTC) ] -->
    Certificate: <none>
    Ephemeral Public Key: <none>
    Data: <none>
    Signature: <none>

Example for encrypted flow (rcv):

  OAP_HDR [4ff83072e0ed54b3 @ 2025-08-05 17:06:23 (UTC) ] <--
    Certificate: <none>
    Ephemeral Public Key [91 bytes]:
    Data: <none>
    Signature: <none>

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

5 files changed, 89 insertions, 3 deletions

diff --git a/src/irmd/CMakeLists.txt b/src/irmd/CMakeLists.txt
index fce89bef..312578de 100644
--- a/src/irmd/CMakeLists.txt
+++ b/src/irmd/CMakeLists.txt
@@ -62,6 +62,8 @@ set(IRMD_PKILL_TIMEOUT 30 CACHE STRING
   "Number of seconds to wait before sending SIGKILL to subprocesses on exit")
 set(IRMD_KILL_ALL_PROCESSES TRUE CACHE BOOL
   "Kill all processes on exit")
+set(DEBUG_PROTO_OAP FALSE CACHE BOOL
+  "Add Flow allocation protocol message output to IRMd debug logging")
 
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/config.h.in"
   "${CMAKE_CURRENT_BINARY_DIR}/config.h" @ONLY)
diff --git a/src/irmd/config.h.in b/src/irmd/config.h.in
index aa37b0ac..11b9d11f 100644
--- a/src/irmd/config.h.in
+++ b/src/irmd/config.h.in
@@ -67,6 +67,7 @@
 #cmakedefine IRMD_KILL_ALL_PROCESSES
 #cmakedefine HAVE_LIBGCRYPT
 #cmakedefine HAVE_OPENSSL
+#cmakedefine DEBUG_PROTO_OAP
 
 #define O7S_ASCII_ART                                                          \
 "\n"                                                                       \
diff --git a/src/irmd/main.c b/src/irmd/main.c
index a5c4001e..bf94354f 100644
--- a/src/irmd/main.c
+++ b/src/irmd/main.c
@@ -830,7 +830,9 @@ static int flow_accept(struct flow_info * flow,
 
         if (delta < -TIMESYNC_SLACK)
                 log_warn("Flow alloc sent from the future (%zd ms).", -delta);
-
+#ifdef DEBUG_PROTO_OAP
+        debug_oap_hdr_rcv(&oap_hdr);
+#endif
         if (flow->qs.cypher_s != 0) {     /* crypto requested           */
                 uint8_t * s;              /* symmetric encryption key   */
                 ssize_t   key_len;        /* length of local pubkey     */
@@ -875,7 +877,9 @@ static int flow_accept(struct flow_info * flow,
                 err = -ENOMEM;
                 goto fail_r_oap_hdr;
         }
-
+#ifdef DEBUG_PROTO_OAP
+        debug_oap_hdr_snd(&oap_hdr);
+#endif
         if (ipcp_flow_alloc_resp(flow, 0, r_oap_hdr.hdr) < 0) {
                 log_err("Failed to respond to flow allocation.");
                 goto fail_resp;
@@ -1101,6 +1105,9 @@ static int flow_alloc(struct flow_info * flow,
                 err = -ENOMEM;
                 goto fail_oap_hdr;
         }
+#ifdef DEBUG_PROTO_OAP
+        debug_oap_hdr_snd(&oap_hdr);
+#endif
 
         log_info("Allocating flow for %d to %s.", flow->n_pid, dst);
 
@@ -1154,7 +1161,9 @@ static int flow_alloc(struct flow_info * flow,
                 err = -EIPCP;
                 goto fail_r_oap_hdr;
         }
-
+#ifdef DEBUG_PROTO_OAP
+        debug_oap_hdr_rcv(&r_oap_hdr);
+#endif
         if (memcmp(r_oap_hdr.id.data, oap_hdr.id.data, r_oap_hdr.id.len) != 0) {
                 log_err("OAP ID mismatch in flow allocation.");
                 err = -EIPCP;
diff --git a/src/irmd/oap.c b/src/irmd/oap.c
index d5e5b7cc..500da6f1 100644
--- a/src/irmd/oap.c
+++ b/src/irmd/oap.c
@@ -26,10 +26,16 @@
  #define _POSIX_C_SOURCE 200809L
 #endif
 
+#define OUROBOROS_PREFIX "irmd/oap"
+
 #include <ouroboros/crypt.h>
 #include <ouroboros/endian.h>
+#include <ouroboros/logs.h>
+#include <ouroboros/rib.h>
 #include <ouroboros/time.h>
 
+#include "config.h"
+
 #include "oap.h"
 
 #include <assert.h>
@@ -217,4 +223,66 @@ int oap_hdr_decode(buffer_t             hdr,
         return -1;
 }
 
+#ifdef DEBUG_PROTO_OAP
+static void debug_oap_hdr(const struct oap_hdr * hdr)
+{
+        assert(hdr);
+
+        if (hdr->crt.len > 0)
+                log_proto("  Certificate: [%zu bytes]", hdr->crt.len);
+        else
+                log_proto("  Certificate: <none>");
+
+        if (hdr->eph.len > 0)
+                log_proto("  Ephemeral Public Key: [%zu bytes]", hdr->eph.len);
+        else
+                log_proto("  Ephemeral Public Key: <none>");
+        if (hdr->data.len > 0)
+                log_proto("  Data: [%zu bytes]", hdr->data.len);
+        else
+                log_proto("  Data: <none>");
+        if (hdr->sig.len > 0)
+                log_proto("  Signature: [%zu bytes]", hdr->sig.len);
+        else
+                log_proto("  Signature: <none>");
+}
+
+void debug_oap_hdr_rcv(const struct oap_hdr *   hdr)
+{
+        struct tm *     tm;
+        char            tmstr[RIB_TM_STRLEN];
+        time_t          stamp;
+
+        assert(hdr);
+
+        stamp = (time_t) hdr->timestamp / BILLION;
+
+        tm = gmtime(&stamp);
+        strftime(tmstr, sizeof(tmstr), RIB_TM_FORMAT, tm);
+
+        log_proto("OAP_HDR [" HASH_FMT64 " @ %s ] <--",
+                  HASH_VAL64(hdr->id.data), tmstr);
+
+        debug_oap_hdr(hdr);
+}
+
+void debug_oap_hdr_snd(const struct oap_hdr * hdr)
+{
+        struct tm *     tm;
+        char            tmstr[RIB_TM_STRLEN];
+        time_t          stamp;
+
+        assert(hdr);
+
+        stamp = (time_t) hdr->timestamp / BILLION;
+
+        tm = gmtime(&stamp);
+        strftime(tmstr, sizeof(tmstr), RIB_TM_FORMAT, tm);
+
+        log_proto("OAP_HDR [" HASH_FMT64 " @ %s ] -->",
+                  HASH_VAL64(hdr->id.data), tmstr);
+
+        debug_oap_hdr(hdr);
+}
+#endif
 
diff --git a/src/irmd/oap.h b/src/irmd/oap.h
index 460a89de..ccdfa804 100644
--- a/src/irmd/oap.h
+++ b/src/irmd/oap.h
@@ -85,4 +85,10 @@ void oap_hdr_fini(struct oap_hdr * oap_hdr);
 int  oap_hdr_decode(buffer_t         hdr,
                     struct oap_hdr * oap_hdr);
 
+#ifdef DEBUG_PROTO_OAP
+void debug_oap_hdr_snd(const struct oap_hdr * hdr);
+
+void debug_oap_hdr_rcv(const struct oap_hdr * hdr);
+#endif /* DEBUG_PROTO_OAP */
+
 #endif /* OUROBOROS_IRMD_OAP_H */