This allows us to control the algorithm used to spread traffic between
sockets, adding more fine grained control. If the user does not
specify a fanout mode, the PMD driver will default to
PACKET_FANOUT_HASH.

Signed-off-by: Tudor Cornea <tudor.cor...@gmail.com>

---
v2:
* Renamed the patch
* Replaced packet_fanout argument with fanout_mode, which allows
more fine grained control
---
 doc/guides/nics/af_packet.rst             |  4 +-
 drivers/net/af_packet/rte_eth_af_packet.c | 92 ++++++++++++++++++++---
 2 files changed, 83 insertions(+), 13 deletions(-)

diff --git a/doc/guides/nics/af_packet.rst b/doc/guides/nics/af_packet.rst
index a343d3a961..3443f95004 100644
--- a/doc/guides/nics/af_packet.rst
+++ b/doc/guides/nics/af_packet.rst
@@ -25,6 +25,8 @@ Some of these, in turn, will be used to configure the 
PACKET_MMAP settings.
 *   ``qpairs`` - number of Rx and Tx queues (optional, default 1);
 *   ``qdisc_bypass`` - set PACKET_QDISC_BYPASS option in AF_PACKET (optional,
     disabled by default);
+*   ``fanout_mode`` - set fanout algorithm. Possible choices: 
hash,lb,cpu,rollover,rnd,qm (optional,
+    default hash);
 *   ``blocksz`` - PACKET_MMAP block size (optional, default 4096);
 *   ``framesz`` - PACKET_MMAP frame size (optional, default 2048B; Note: 
multiple
     of 16B);
@@ -64,7 +66,7 @@ framecnt=512):
 
 .. code-block:: console
 
-    
--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,framecnt=512,qpairs=1,qdisc_bypass=0
+    
--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,framecnt=512,qpairs=1,qdisc_bypass=0,fanout_mode=hash
 
 Features and Limitations
 ------------------------
diff --git a/drivers/net/af_packet/rte_eth_af_packet.c 
b/drivers/net/af_packet/rte_eth_af_packet.c
index ceb8d9356a..8449975384 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -36,6 +36,7 @@
 #define ETH_AF_PACKET_FRAMESIZE_ARG    "framesz"
 #define ETH_AF_PACKET_FRAMECOUNT_ARG   "framecnt"
 #define ETH_AF_PACKET_QDISC_BYPASS_ARG "qdisc_bypass"
+#define ETH_AF_PACKET_FANOUT_MODE_ARG  "fanout_mode"
 
 #define DFLT_FRAME_SIZE                (1 << 11)
 #define DFLT_FRAME_COUNT       (1 << 9)
@@ -96,6 +97,7 @@ static const char *valid_arguments[] = {
        ETH_AF_PACKET_FRAMESIZE_ARG,
        ETH_AF_PACKET_FRAMECOUNT_ARG,
        ETH_AF_PACKET_QDISC_BYPASS_ARG,
+       ETH_AF_PACKET_FANOUT_MODE_ARG,
        NULL
 };
 
@@ -700,6 +702,61 @@ open_packet_iface(const char *key __rte_unused,
        return 0;
 }
 
+#if defined(PACKET_FANOUT)
+#define PACKET_FANOUT_INVALID -1
+
+static int
+get_fanout_group_id(int if_index)
+{
+       return (getpid() ^ if_index) & 0xffff;
+}
+
+static int
+get_fanout_mode(const char *fanout_mode)
+{
+       int mode = PACKET_FANOUT_FLAG_DEFRAG;
+
+#if defined(PACKET_FANOUT_FLAG_ROLLOVER)
+       mode |= PACKET_FANOUT_FLAG_ROLLOVER;
+#endif
+
+       if (!fanout_mode) {
+               /* Default */
+               mode |= PACKET_FANOUT_HASH;
+       } else if (!strcmp(fanout_mode, "hash")) {
+               mode |= PACKET_FANOUT_HASH;
+       } else if (!strcmp(fanout_mode, "lb")) {
+               mode |= PACKET_FANOUT_LB;
+       } else if (!strcmp(fanout_mode, "cpu")) {
+               mode |= PACKET_FANOUT_CPU;
+       } else if (!strcmp(fanout_mode, "rollover")) {
+               mode |= PACKET_FANOUT_ROLLOVER;
+       } else if (!strcmp(fanout_mode, "rnd")) {
+               mode |= PACKET_FANOUT_RND;
+       } else if (!strcmp(fanout_mode, "qm")) {
+               mode |= PACKET_FANOUT_QM;
+       } else {
+               /* Invalid Fanout Mode */
+               mode = PACKET_FANOUT_INVALID;
+       }
+
+       return mode;
+}
+
+static int
+get_fanout(const char *fanout_mode, int if_index)
+{
+       int group_id = get_fanout_group_id(if_index);
+       int mode = get_fanout_mode(fanout_mode);
+       int fanout = PACKET_FANOUT_INVALID;
+
+       if (mode != PACKET_FANOUT_INVALID)
+               fanout = group_id | (mode << 16);
+
+       return fanout;
+}
+#endif
+
 static int
 rte_pmd_init_internals(struct rte_vdev_device *dev,
                        const int sockfd,
@@ -709,6 +766,7 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
                        unsigned int framesize,
                        unsigned int framecnt,
                       unsigned int qdisc_bypass,
+                      const char *fanout_mode,
                        struct pmd_internals **internals,
                        struct rte_eth_dev **eth_dev,
                        struct rte_kvargs *kvlist)
@@ -810,11 +868,12 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
        sockaddr.sll_ifindex = (*internals)->if_index;
 
 #if defined(PACKET_FANOUT)
-       fanout_arg = (getpid() ^ (*internals)->if_index) & 0xffff;
-       fanout_arg |= (PACKET_FANOUT_HASH | PACKET_FANOUT_FLAG_DEFRAG) << 16;
-#if defined(PACKET_FANOUT_FLAG_ROLLOVER)
-       fanout_arg |= PACKET_FANOUT_FLAG_ROLLOVER << 16;
-#endif
+       fanout_arg = get_fanout(fanout_mode, (*internals)->if_index);
+
+       if (fanout_arg == PACKET_FANOUT_INVALID) {
+               PMD_LOG(ERR, "Invalid fanout mode: %s", fanout_mode);
+               goto error;
+       }
 #endif
 
        for (q = 0; q < nb_queues; q++) {
@@ -927,13 +986,16 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
                }
 
 #if defined(PACKET_FANOUT)
-               rc = setsockopt(qsockfd, SOL_PACKET, PACKET_FANOUT,
-                               &fanout_arg, sizeof(fanout_arg));
-               if (rc == -1) {
-                       PMD_LOG_ERRNO(ERR,
-                               "%s: could not set PACKET_FANOUT on AF_PACKET 
socket for %s",
-                               name, pair->value);
-                       goto error;
+               if (nb_queues > 1) {
+                       rc = setsockopt(qsockfd, SOL_PACKET, PACKET_FANOUT,
+                                       &fanout_arg, sizeof(fanout_arg));
+                       if (rc == -1) {
+                               PMD_LOG_ERRNO(ERR,
+                                       "%s: could not set PACKET_FANOUT "
+                                       "on AF_PACKET socket for %s",
+                                       name, pair->value);
+                               goto error;
+                       }
                }
 #endif
        }
@@ -1003,6 +1065,7 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
        unsigned int framecount = DFLT_FRAME_COUNT;
        unsigned int qpairs = 1;
        unsigned int qdisc_bypass = 1;
+       const char *fanout_mode = NULL;
 
        /* do some parameter checking */
        if (*sockfd < 0)
@@ -1065,6 +1128,10 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
                        }
                        continue;
                }
+               if (strstr(pair->key, ETH_AF_PACKET_FANOUT_MODE_ARG) != NULL) {
+                       fanout_mode = pair->value;
+                       continue;
+               }
        }
 
        if (framesize > blocksize) {
@@ -1091,6 +1158,7 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
                                   blocksize, blockcount,
                                   framesize, framecount,
                                   qdisc_bypass,
+                                  fanout_mode,
                                   &internals, &eth_dev,
                                   kvlist) < 0)
                return -1;
-- 
2.34.1

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