[PATCH BlueZ v1] bthost: Add segmentation support for L2CAP LE-(E)CRED mode

[PATCH BlueZ v1] bthost: Add segmentation support for L2CAP LE-(E)CRED mode

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

---
 emulator/bthost.c | 53 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 12 deletions(-)

diff --git a/emulator/bthost.c b/emulator/bthost.c
index 53b12f828675..b913c8015416 100644
--- a/emulator/bthost.c
+++ b/emulator/bthost.c
@@ -22,6 +22,7 @@
 #include <endian.h>
 #include <errno.h>
 #include <stdbool.h>
+#include <sys/param.h>
 
 #include "bluetooth/bluetooth.h"
 
@@ -185,6 +186,8 @@ struct l2conn {
 	uint16_t scid;
 	uint16_t dcid;
 	uint16_t psm;
+	uint16_t rx_mps;
+	uint16_t tx_mps;
 	uint16_t rx_credits;
 	uint16_t tx_credits;
 	enum l2cap_mode mode;
@@ -748,14 +751,14 @@ static void send_iov(struct bthost *bthost, uint16_t handle, uint16_t cid,
 }
 
 static void send_acl(struct bthost *bthost, uint16_t handle, uint16_t cid,
-				bool sdu_hdr, const void *data, uint16_t len)
+			uint16_t sdu_len, const void *data, uint16_t len)
 {
 	struct iovec iov[2];
 	uint16_t sdu;
 	int num = 0;
 
-	if (sdu_hdr) {
-		sdu = cpu_to_le16(len);
+	if (sdu_len) {
+		sdu = cpu_to_le16(sdu_len);
 		iov[num].iov_base = &sdu;
 		iov[num].iov_len = sizeof(sdu);
 		num++;
@@ -885,18 +888,42 @@ void bthost_send_cid(struct bthost *bthost, uint16_t handle, uint16_t cid,
 {
 	struct btconn *conn;
 	struct l2conn *l2conn;
-	bool sdu_hdr = false;
+	struct iovec iov = {
+		.iov_base = (void *) data,
+		.iov_len = len,
+	};
 
 	conn = bthost_find_conn(bthost, handle);
 	if (!conn)
 		return;
 
 	l2conn = btconn_find_l2cap_conn_by_dcid(conn, cid);
-	if (l2conn && (l2conn->mode == L2CAP_MODE_LE_CRED ||
-			l2conn->mode == L2CAP_MODE_LE_ENH_CRED))
-		sdu_hdr = true;
 
-	send_acl(bthost, handle, cid, sdu_hdr, data, len);
+	/* Segment SDU in case of LE (Enhanced) Credit Based Flow Control */
+	if (l2conn && (l2conn->mode == L2CAP_MODE_LE_CRED ||
+			l2conn->mode == L2CAP_MODE_LE_ENH_CRED)) {
+		uint16_t sdu_len = len;
+		uint16_t slen;
+		int i;
+
+		for (i = 0; iov.iov_len; i++) {
+			if (sdu_len)
+				slen = MIN(iov.iov_len,
+					l2conn->tx_mps - sizeof(sdu_len));
+			else
+				slen = MIN(iov.iov_len, l2conn->tx_mps);
+
+			send_acl(bthost, handle, cid, sdu_len,
+					util_iov_pull_mem(&iov, slen), slen);
+
+			if (sdu_len)
+				sdu_len = 0;
+		}
+
+		return;
+	}
+
+	send_acl(bthost, handle, cid, 0, data, len);
 }
 
 void bthost_send_cid_v(struct bthost *bthost, uint16_t handle, uint16_t cid,
@@ -2104,7 +2131,7 @@ static void rfcomm_sabm_send(struct bthost *bthost, struct btconn *conn,
 	cmd.length = RFCOMM_LEN8(0);
 	cmd.fcs = rfcomm_fcs2((uint8_t *)&cmd);
 
-	send_acl(bthost, conn->handle, l2conn->dcid, false, &cmd, sizeof(cmd));
+	send_acl(bthost, conn->handle, l2conn->dcid, 0, &cmd, sizeof(cmd));
 }
 
 static bool l2cap_conn_rsp(struct bthost *bthost, struct btconn *conn,
@@ -2501,6 +2528,8 @@ static bool l2cap_le_conn_req(struct bthost *bthost, struct btconn *conn,
 							le16_to_cpu(req->scid),
 							le16_to_cpu(psm));
 		l2conn->mode = L2CAP_MODE_LE_CRED;
+		l2conn->rx_mps = le16_to_cpu(rsp.mps);
+		l2conn->tx_mps = le16_to_cpu(req->mps);
 		l2conn->rx_credits = le16_to_cpu(rsp.credits);
 		l2conn->tx_credits = le16_to_cpu(req->credits);
 
@@ -2749,7 +2778,7 @@ static void rfcomm_ua_send(struct bthost *bthost, struct btconn *conn,
 	cmd.length = RFCOMM_LEN8(0);
 	cmd.fcs = rfcomm_fcs2((uint8_t *)&cmd);
 
-	send_acl(bthost, conn->handle, l2conn->dcid, false, &cmd, sizeof(cmd));
+	send_acl(bthost, conn->handle, l2conn->dcid, 0, &cmd, sizeof(cmd));
 }
 
 static void rfcomm_dm_send(struct bthost *bthost, struct btconn *conn,
@@ -2763,7 +2792,7 @@ static void rfcomm_dm_send(struct bthost *bthost, struct btconn *conn,
 	cmd.length = RFCOMM_LEN8(0);
 	cmd.fcs = rfcomm_fcs2((uint8_t *)&cmd);
 
-	send_acl(bthost, conn->handle, l2conn->dcid, false, &cmd, sizeof(cmd));
+	send_acl(bthost, conn->handle, l2conn->dcid, 0, &cmd, sizeof(cmd));
 }
 
 static void rfcomm_sabm_recv(struct bthost *bthost, struct btconn *conn,
@@ -4199,7 +4228,7 @@ void bthost_send_rfcomm_data(struct bthost *bthost, uint16_t handle,
 	}
 
 	uih_frame[uih_len - 1] = rfcomm_fcs((void *)hdr);
-	send_acl(bthost, handle, rcconn->scid, false, uih_frame, uih_len);
+	send_acl(bthost, handle, rcconn->scid, 0, uih_frame, uih_len);
 
 	free(uih_frame);
 }
-- 
2.52.0

RE: [BlueZ,v1] bthost: Add segmentation support for L2CAP LE-(E)CRED mode

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1689 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=1058038

---Test result---

Test Summary:
CheckPatch                    PENDING   0.31 seconds
GitLint                       PENDING   0.33 seconds
BuildEll                      PASS      21.37 seconds
BluezMake                     PASS      649.60 seconds
MakeCheck                     PASS      18.51 seconds
MakeDistcheck                 PASS      254.13 seconds
CheckValgrind                 PASS      299.90 seconds
CheckSmatch                   WARNING   364.01 seconds
bluezmakeextell               PASS      183.50 seconds
IncrementalBuild              PENDING   0.65 seconds
ScanBuild                     PASS      1036.94 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: CheckSmatch - WARNING
Desc: Run smatch tool with source
Output:
emulator/bthost.c:703:28: warning: Variable length array is used.emulator/bthost.c:704:32: warning: Variable length array is used.emulator/bthost.c:945:28: warning: Variable length array is used.emulator/bthost.c:979:28: warning: Variable length array is used.emulator/bthost.c:980:32: warning: Variable length array is used.
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH BlueZ v1] bthost: Add segmentation support for L2CAP LE-(E)CRED mode

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluez.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Wed, 25 Feb 2026 17:23:45 -0500 you wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> ---
>  emulator/bthost.c | 53 ++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 41 insertions(+), 12 deletions(-)

Here is the summary with links:
  - [BlueZ,v1] bthost: Add segmentation support for L2CAP LE-(E)CRED mode
    https://git.kernel.org/pub/scm/bluetooth/bluez.git/?id=b138a0849ba2

You are awesome, thank you!
-- 
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