diff --git a/libc-test/build.rs b/libc-test/build.rs
index 778b24b2d5e5e..3aeb0a9e2c270 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -2445,7 +2445,8 @@ fn test_freebsd(target: &str) {
                 "sys/shm.h",
                 "sys/socket.h",
                 "sys/socketvar.h",
-                "netinet/in_pcb.h",	// must be after sys/socketvar.h
+                [freebsd15]:"sys/ktls.h",
+                "netinet/in_pcb.h",	// must be after sys/socketvar.h, sys/ktls.h
                 "sys/stat.h",
                 "sys/statvfs.h",
                 "sys/sysctl.h",
@@ -2527,6 +2528,8 @@ fn test_freebsd(target: &str) {
             "type_" if struct_ == "sockstat" => "type".to_string(),
             "type_" if struct_ == "devstat_match_table" => "type".to_string(),
             "type_" if struct_ == "input_event" => "type".to_string(),
+            // Field is named `gennum` in Rust because `gen` is a keyword
+            "gennum" if struct_ == "xktls_session_onedir" => "gen".to_string(),
             s => s.to_string(),
         }
     });
diff --git a/src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs b/src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs
index 6b9eb1271184f..3fc141c7941bb 100644
--- a/src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs
@@ -226,6 +226,8 @@ s! {
         // This is normally "struct pwddesc".
         /// Pointer to process paths info.
         pub ki_pd: *mut c_void,
+        /// Address of the ext err msg place
+        pub ki_uerrmsg: *mut c_void,
         pub ki_spareptrs: [*mut c_void; crate::KI_NSPARE_PTR],
         pub ki_sparelongs: [c_long; crate::KI_NSPARE_LONG],
         /// PS_* flags.
@@ -445,7 +447,7 @@ pub const KF_TYPE_EVENTFD: c_int = 13;
 
 /// max length of devicename
 pub const SPECNAMELEN: c_int = 255;
-pub const KI_NSPARE_PTR: usize = 5;
+pub const KI_NSPARE_PTR: usize = 4;
 
 /// domainset policies
 pub const DOMAINSET_POLICY_INVALID: c_int = 0;
diff --git a/src/unix/bsd/freebsdlike/freebsd/mod.rs b/src/unix/bsd/freebsdlike/freebsd/mod.rs
index 7c420d703cc0f..26d9bb9395179 100644
--- a/src/unix/bsd/freebsdlike/freebsd/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/mod.rs
@@ -1762,6 +1762,8 @@ s_no_extra_traits! {
     }
 
     pub struct xktls_session_onedir {
+        // Note: this field is called `gen` in upstream FreeBSD, but `gen` is
+        // reserved keyword in Rust since the 2024 Edition, hence `gennum`.
         pub gennum: u64,
         _rsrv1: [u64; 8],
         _rsrv2: [u32; 8],
@@ -1779,7 +1781,7 @@ s_no_extra_traits! {
         pub tls_bs: u8,
         pub flags: u8,
         pub drv_st_len: u16,
-        pub ifnet: [u8; 16],
+        pub ifnet: [c_char; 16],
     }
 
     pub struct xktls_session {