[PATCH v4] nvme-tcp: Print actual source IP address through sysfs "address" attr
From: Martin Belanger <hidden>
Date: 2022-09-07 12:28:13
From: Martin Belanger <redacted> 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 exposes the actual source address using a new field named "src_addr=" in the "address" attribute. This is needed to diagnose and identify connectivity issues. With the source address we can infer the interface associated with each connection. This was tested with nvme-cli 2.0 to verify it does not have any adverse effect. The new "src_addr=" field will simply be displayed in the output of the "list-subsys" or "list -v" commands as shown here. $ nvme list-subsys nvme-subsys0 - NQN=nqn.2014-08.org.nvmexpress.discovery \ +- nvme0 tcp traddr=192.168.56.1,trsvcid=8009,src_addr=192.168.56.101 live Changes to v3: Per Chaitanya review comments: Change the order of the variables declaration. And although len can never be 0, for completeness add a check (lev > 0) before decrementing its value. Changes to v2: Taken Sagi's comments into account Changes to original submission: Reword comments per Chaitanya's suggestion Signed-off-by: Martin Belanger <redacted> --- drivers/nvme/host/tcp.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 044da18c06f5..e1e77de17f66 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c@@ -2532,6 +2532,25 @@ 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) +{ + struct nvme_tcp_queue *queue = &to_tcp_ctrl(ctrl)->queues[0]; + struct sockaddr_storage src_addr; + int ret, len; + + len = nvmf_get_address(ctrl, buf, size); + + ret = kernel_getsockname(queue->sock, (struct sockaddr *)&src_addr); + if (ret > 0) { + if (len > 0) + len--; /* strip trailing newline */ + len += scnprintf(buf + len, size - len, "%ssrc_addr=%pISc\n", + (len) ? "," : "", &src_addr); + } + + 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 +2582,7 @@ 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, };
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2.37.2