net/af_xdp: custom XDP program loading
diff mbox series

Message ID 20200828111812.31986-1-ciara.loftus@intel.com
State Superseded
Delegated to: Ferruh Yigit
Headers show
Series
  • net/af_xdp: custom XDP program loading
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ci/checkpatch success coding style OK
ci/iol-mellanox-Performance success Performance Testing PASS
ci/iol-testing success Testing PASS
ci/travis-robot success Travis build: passed
ci/Intel-compilation success Compilation OK

Commit Message

Loftus, Ciara Aug. 28, 2020, 11:18 a.m. UTC
The new 'xdp_prog=<string>' vdev arg allows the user to specify the path to
a custom XDP program to be set on the device, instead of the default libbpf
one. The program must have an XSK_MAP of name 'xsks_map' which will allow
for the redirection of some packets to userspace and thus the PMD, using
some criteria defined in the program.
Note: a netdev may only load one program.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
---
 doc/guides/nics/af_xdp.rst          |   1 +
 drivers/net/af_xdp/rte_eth_af_xdp.c | 100 ++++++++++++++++++++++++++--
 2 files changed, 95 insertions(+), 6 deletions(-)

Comments

Tahhan, Maryam Sept. 10, 2020, 11:40 a.m. UTC | #1
> -----Original Message-----
> From: Loftus, Ciara <ciara.loftus@intel.com>
> Sent: Friday 28 August 2020 12:18
> To: dev@dpdk.org
> Cc: Loftus, Ciara <ciara.loftus@intel.com>
> Subject: [PATCH] net/af_xdp: custom XDP program loading
> 
> The new 'xdp_prog=<string>' vdev arg allows the user to specify the path to
> a custom XDP program to be set on the device, instead of the default libbpf
> one. The program must have an XSK_MAP of name 'xsks_map' which will
> allow for the redirection of some packets to userspace and thus the PMD,
> using some criteria defined in the program.
> Note: a netdev may only load one program.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> ---

[MT] Stupid question :), AF_XDP is specifically related to loading an XDP program that allows you to redirect packets to an XSK... 
why would you want to allow a custom XDP program to be loaded? 

Other than that the code itself looked GTM

<snip>
Loftus, Ciara Sept. 14, 2020, 1:07 p.m. UTC | #2
> >
> > The new 'xdp_prog=<string>' vdev arg allows the user to specify the path
> to
> > a custom XDP program to be set on the device, instead of the default libbpf
> > one. The program must have an XSK_MAP of name 'xsks_map' which will
> > allow for the redirection of some packets to userspace and thus the PMD,
> > using some criteria defined in the program.
> > Note: a netdev may only load one program.
> >
> > Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> > ---
> 
> [MT] Stupid question :), AF_XDP is specifically related to loading an XDP
> program that allows you to redirect packets to an XSK...
> why would you want to allow a custom XDP program to be loaded?
> 
> Other than that the code itself looked GTM

Hi Maryam,

Thanks for your feedback. It's a good question, and I will update the commit message in the v2 with the reasoning.

Sometimes it might be desired to redirect some not all packets to the xsk/PMD. eg. if the user wishes to drop or process a certain type of packet in the kernel. That logic can be put in the custom program. The key is that the custom program allows for *some* packets to still hit the xsk, and we check for that through checking the presence of the xsks_map.

Thanks,
Ciara

> 
> <snip>
Hu, Xuekun Sept. 18, 2020, 2:54 a.m. UTC | #3
> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Ciara Loftus
> Sent: Friday, August 28, 2020 7:18 PM
> To: dev@dpdk.org
> Cc: Loftus, Ciara <ciara.loftus@intel.com>
> Subject: [dpdk-dev] [PATCH] net/af_xdp: custom XDP program loading
> 
> The new 'xdp_prog=<string>' vdev arg allows the user to specify the path to a
> custom XDP program to be set on the device, instead of the default libbpf
> one. The program must have an XSK_MAP of name 'xsks_map' which will
> allow for the redirection of some packets to userspace and thus the PMD,
> using some criteria defined in the program.
> Note: a netdev may only load one program.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> ---

Tested-by: Xuekun Hu <xuekun.hu@intel.com)>

Patch
diff mbox series

diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index 07bdd29e29..19aefa80e8 100644
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -32,6 +32,7 @@  The following options can be provided to set up an af_xdp port in DPDK.
 *   ``iface`` - name of the Kernel interface to attach to (required);
 *   ``start_queue`` - starting netdev queue id (optional, default 0);
 *   ``queue_count`` - total netdev queue number (optional, default 1);
+*   ``xdp_prog`` - path to custom xdp program (optional, default none);
 
 Prerequisites
 -------------
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 936d4a7d5f..6f70dba538 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -1,5 +1,5 @@ 
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2019 Intel Corporation.
+ * Copyright(c) 2020 Intel Corporation.
  */
 #include <unistd.h>
 #include <errno.h>
@@ -118,6 +118,8 @@  struct pmd_internals {
 	int queue_cnt;
 	int max_queue_cnt;
 	int combined_queue_cnt;
+	char prog_path[PATH_MAX];
+	bool custom_prog_configured;
 
 	struct rte_ether_addr eth_addr;
 
@@ -128,11 +130,13 @@  struct pmd_internals {
 #define ETH_AF_XDP_IFACE_ARG			"iface"
 #define ETH_AF_XDP_START_QUEUE_ARG		"start_queue"
 #define ETH_AF_XDP_QUEUE_COUNT_ARG		"queue_count"
+#define ETH_AF_XDP_PROG_ARG			"xdp_prog"
 
 static const char * const valid_arguments[] = {
 	ETH_AF_XDP_IFACE_ARG,
 	ETH_AF_XDP_START_QUEUE_ARG,
 	ETH_AF_XDP_QUEUE_COUNT_ARG,
+	ETH_AF_XDP_PROG_ARG,
 	NULL
 };
 
@@ -863,6 +867,45 @@  xsk_umem_info *xdp_umem_configure(struct pmd_internals *internals,
 	return NULL;
 }
 
+static int
+load_custom_xdp_prog(const char *prog_path, int if_index)
+{
+	int ret, prog_fd = -1;
+	struct bpf_object *obj;
+	struct bpf_map *map;
+
+	ret = bpf_prog_load(prog_path, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
+	if (ret) {
+		AF_XDP_LOG(ERR, "Failed to load program %s\n", prog_path);
+		return ret;
+	}
+
+	/*
+	 * The loaded program must provision for a map of xsks, such that some
+	 * traffic can be redirected to userspace. When the xsk is created,
+	 * libbpf inserts it into the map.
+	 */
+	map = bpf_object__find_map_by_name(obj, "xsks_map");
+	if (!map) {
+		AF_XDP_LOG(ERR, "Failed to find xsks_map in %s\n", prog_path);
+		return -1;
+	}
+
+	/* Link the program with the given network device */
+	ret = bpf_set_link_xdp_fd(if_index, prog_fd,
+					XDP_FLAGS_UPDATE_IF_NOEXIST);
+	if (ret) {
+		AF_XDP_LOG(ERR, "Failed to set prog fd %d on interface\n",
+				prog_fd);
+		return -1;
+	}
+
+	AF_XDP_LOG(INFO, "Successfully loaded XDP program %s with fd %d\n",
+				prog_path, prog_fd);
+
+	return 0;
+}
+
 static int
 xsk_configure(struct pmd_internals *internals, struct pkt_rx_queue *rxq,
 	      int ring_size)
@@ -888,6 +931,18 @@  xsk_configure(struct pmd_internals *internals, struct pkt_rx_queue *rxq,
 	cfg.bind_flags |= XDP_USE_NEED_WAKEUP;
 #endif
 
+	if (strnlen(internals->prog_path, PATH_MAX) &&
+				!internals->custom_prog_configured) {
+		ret = load_custom_xdp_prog(internals->prog_path,
+					   internals->if_index);
+		if (ret) {
+			AF_XDP_LOG(ERR, "Failed to load custom XDP program %s\n",
+					internals->prog_path);
+			goto err;
+		}
+		internals->custom_prog_configured = 1;
+	}
+
 	ret = xsk_socket__create(&rxq->xsk, internals->if_name,
 			rxq->xsk_queue_idx, rxq->umem->umem, &rxq->rx,
 			&txq->tx, &cfg);
@@ -1099,6 +1154,30 @@  parse_name_arg(const char *key __rte_unused,
 	return 0;
 }
 
+/** parse xdp prog argument */
+static int
+parse_prog_arg(const char *key __rte_unused,
+	       const char *value, void *extra_args)
+{
+	char *path = extra_args;
+
+	if (strnlen(value, PATH_MAX) > PATH_MAX - 1) {
+		AF_XDP_LOG(ERR, "Invalid path %s, should be less than %u bytes.\n",
+			   value, PATH_MAX);
+		return -EINVAL;
+	}
+
+	if (access(value, F_OK) != 0) {
+		AF_XDP_LOG(ERR, "Error accessing %s: %s\n",
+			   value, strerror(errno));
+		return -EINVAL;
+	}
+
+	strlcpy(path, value, PATH_MAX);
+
+	return 0;
+}
+
 static int
 xdp_get_channels_info(const char *if_name, int *max_queues,
 				int *combined_queues)
@@ -1142,7 +1221,7 @@  xdp_get_channels_info(const char *if_name, int *max_queues,
 
 static int
 parse_parameters(struct rte_kvargs *kvlist, char *if_name, int *start_queue,
-			int *queue_cnt)
+			int *queue_cnt, char *prog_path)
 {
 	int ret;
 
@@ -1163,6 +1242,11 @@  parse_parameters(struct rte_kvargs *kvlist, char *if_name, int *start_queue,
 		goto free_kvlist;
 	}
 
+	ret = rte_kvargs_process(kvlist, ETH_AF_XDP_PROG_ARG,
+				 &parse_prog_arg, prog_path);
+	if (ret < 0)
+		goto free_kvlist;
+
 free_kvlist:
 	rte_kvargs_free(kvlist);
 	return ret;
@@ -1200,7 +1284,7 @@  get_iface_info(const char *if_name,
 
 static struct rte_eth_dev *
 init_internals(struct rte_vdev_device *dev, const char *if_name,
-			int start_queue_idx, int queue_cnt)
+		int start_queue_idx, int queue_cnt, const char *prog_path)
 {
 	const char *name = rte_vdev_device_name(dev);
 	const unsigned int numa_node = dev->device.numa_node;
@@ -1216,6 +1300,8 @@  init_internals(struct rte_vdev_device *dev, const char *if_name,
 	internals->start_queue_idx = start_queue_idx;
 	internals->queue_cnt = queue_cnt;
 	strlcpy(internals->if_name, if_name, IFNAMSIZ);
+	strlcpy(internals->prog_path, prog_path, PATH_MAX);
+	internals->custom_prog_configured = 0;
 
 	if (xdp_get_channels_info(if_name, &internals->max_queue_cnt,
 				  &internals->combined_queue_cnt)) {
@@ -1292,6 +1378,7 @@  rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
 	char if_name[IFNAMSIZ] = {'\0'};
 	int xsk_start_queue_idx = ETH_AF_XDP_DFLT_START_QUEUE_IDX;
 	int xsk_queue_cnt = ETH_AF_XDP_DFLT_QUEUE_COUNT;
+	char prog_path[PATH_MAX] = {'\0'};
 	struct rte_eth_dev *eth_dev = NULL;
 	const char *name;
 
@@ -1321,7 +1408,7 @@  rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
 		dev->device.numa_node = rte_socket_id();
 
 	if (parse_parameters(kvlist, if_name, &xsk_start_queue_idx,
-			     &xsk_queue_cnt) < 0) {
+			     &xsk_queue_cnt, prog_path) < 0) {
 		AF_XDP_LOG(ERR, "Invalid kvargs value\n");
 		return -EINVAL;
 	}
@@ -1332,7 +1419,7 @@  rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
 	}
 
 	eth_dev = init_internals(dev, if_name, xsk_start_queue_idx,
-					xsk_queue_cnt);
+					xsk_queue_cnt, prog_path);
 	if (eth_dev == NULL) {
 		AF_XDP_LOG(ERR, "Failed to init internals\n");
 		return -1;
@@ -1375,4 +1462,5 @@  RTE_PMD_REGISTER_VDEV(net_af_xdp, pmd_af_xdp_drv);
 RTE_PMD_REGISTER_PARAM_STRING(net_af_xdp,
 			      "iface=<string> "
 			      "start_queue=<int> "
-			      "queue_count=<int> ");
+			      "queue_count=<int> "
+			      "xdp_prog=<string> ");