[PATCH v2] nvme-tcp: Print actual source IP address in address attribute

[Martin Belanger]

From: Martin Belanger <martin.belanger at dell.com>

TCP transport relies on the routing table to determine which
source address and interface to use when making a connection.
Currently, there is no way to tell from userspace where a
connection was made. This patch allows exposing the actual source
address using the host_traddr field of the address attribute.

This is needed to diagnose and identify connectivity issues since it will
allow us to tell which interface and source address is associated with each
connection.

Signed-off-by: Martin Belanger <martin.belanger at dell.com>
---
 drivers/nvme/host/tcp.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 044da18c06f5..adbb76483a74 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -165,6 +165,7 @@ struct nvme_tcp_ctrl {
 	struct blk_mq_tag_set	admin_tag_set;
 	struct sockaddr_storage addr;
 	struct sockaddr_storage src_addr;
+	struct sockaddr_storage sock_addr;
 	struct nvme_ctrl	ctrl;
 
 	struct work_struct	err_work;
@@ -1597,6 +1598,12 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl,
 		goto err_rcv_pdu;
 	}
 
+	/* Retrieve the actual source address from the socket */
+	ret = kernel_getsockname(queue->sock,
+		(struct sockaddr *)&ctrl->sock_addr);
+	if (ret < 0)
+		memset(&ctrl->sock_addr, 0, sizeof(ctrl->sock_addr));
+
 	ret = nvme_tcp_init_connection(queue);
 	if (ret)
 		goto err_init_connect;
@@ -2532,6 +2539,31 @@ static int nvme_tcp_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
 	return queue->nr_cqe;
 }
 
+static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
+{
+	int len = 0;
+	struct sockaddr_storage *sa = &to_tcp_ctrl(ctrl)->sock_addr;
+
+	if (ctrl->opts->mask & NVMF_OPT_TRADDR)
+		len += scnprintf(buf, size, "traddr=%s", ctrl->opts->traddr);
+	if (ctrl->opts->mask & NVMF_OPT_TRSVCID)
+		len += scnprintf(buf + len, size - len, "%strsvcid=%s",
+				(len) ? "," : "", ctrl->opts->trsvcid);
+	if ((sa->ss_family == AF_INET) || (sa->ss_family == AF_INET6)) {
+		len += scnprintf(buf + len, size - len, "%shost_traddr=%pISc",
+				(len) ? "," : "", sa);
+	} else if (ctrl->opts->mask & NVMF_OPT_HOST_TRADDR) {
+		len += scnprintf(buf + len, size - len, "%shost_traddr=%s",
+				(len) ? "," : "", ctrl->opts->host_traddr);
+	}
+	if (ctrl->opts->mask & NVMF_OPT_HOST_IFACE)
+		len += scnprintf(buf + len, size - len, "%shost_iface=%s",
+				(len) ? "," : "", ctrl->opts->host_iface);
+	len += scnprintf(buf + len, size - len, "\n");
+
+	return len;
+}
+
 static const struct blk_mq_ops nvme_tcp_mq_ops = {
 	.queue_rq	= nvme_tcp_queue_rq,
 	.commit_rqs	= nvme_tcp_commit_rqs,
@@ -2563,7 +2595,7 @@ static const struct nvme_ctrl_ops nvme_tcp_ctrl_ops = {
 	.free_ctrl		= nvme_tcp_free_ctrl,
 	.submit_async_event	= nvme_tcp_submit_async_event,
 	.delete_ctrl		= nvme_tcp_delete_ctrl,
-	.get_address		= nvmf_get_address,
+	.get_address		= nvme_tcp_get_address,
 	.stop_ctrl		= nvme_tcp_stop_ctrl,
 };
 
-- 
2.37.2