ota: .mota container format, merkle tree, EndF self-identity, signature verify

src/helpers/ota/FirmwareInfo.cpp

@@ -0,0 +1,42 @@
+#include "FirmwareInfo.h"
+#include "Multihash.h"
+#include "OtaByteIO.h"
+#include <string.h>
+
+namespace mesh {
+namespace ota {
+
+bool find_self_firmware(const uint8_t* region, uint32_t region_len,
+                        SelfFwInfo& out, bool verify_body) {
+  out = SelfFwInfo();
+  if (!region || region_len < ENDF_LEN) return false;
+
+  for (uint32_t off = 0; off + ENDF_LEN <= region_len; off++) {
+    if (region[off] != ENDF_MAGIC[0]) continue;               // cheap pre-filter ('E')
+    if (memcmp(region + off, ENDF_MAGIC, 4) != 0) continue;
+    uint32_t body_len = rd_u32le(region + off + 4);
+    if (body_len != off) continue;                            // trailer must sit right after the body
+
+    if (verify_body) {
+      uint8_t h[8];
+      mh8(h, region, body_len);
+      if (memcmp(h, region + off + 8, 8) != 0) continue;       // coincidental marker — keep scanning
+    }
+    out.valid = true;
+    out.endf_offset = off;
+    out.body_len = body_len;
+    out.image_len = off + ENDF_LEN;
+    memcpy(out.body_hash, region + off + 8, 8);
+    // Fixed 56-byte trailer: the self-describing identity follows body_hash at constant offsets
+    // (fw_version@16, target_id@20, hw_id@24..56). Zero/"" means "unknown".
+    out.fw_version = rd_u32le(region + off + 16);
+    out.target_id  = rd_u32le(region + off + 20);
+    memcpy(out.hw_id, region + off + 24, 32);
+    out.hw_id[32] = 0;
+    return true;
+  }
+  return false;
+}
+
+} // namespace ota
+} // namespace mesh