ethtool: Block setting of symmetric RSS when non-symmetric rx-flow-hash is requested

Symmetric RSS hash requires that:
* No other fields besides IP src/dst and/or L4 src/dst are set
* If src is set, dst must also be set

This restriction was only enforced when RXNFC was configured after
symmetric hash was enabled. In the opposite order of operations (RXNFC
then symmetric enablement) the check was not performed.

Perform the sanity check on set_rxfh as well, by iterating over all flow
types hash fields and making sure they are all symmetric.

Introduce a function that returns whether a flow type is hashable (not
spec only) and needs to be iterated over. To make sure that no one
forgets to update the list of hashable flow types when adding new flow
types, a static assert is added to draw the developer's attention.

The conversion of uapi #defines to enum is not ideal, but as Jakub
mentioned [1], we have precedent for that.

[1] https://lore.kernel.org/netdev/20250324073509.6571ade3@kernel.org/

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250508103034.885536-1-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 84833cca29fec4dcf07626f1094d2e4a230e3301..707c1844010cdb77e32e92285626f73678804ab8 100644 (file)
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -2295,71 +2295,75 @@ static inline int ethtool_validate_duplex(__u8 duplex)
 #define        RXH_XFRM_SYM_OR_XOR     (1 << 1)
 #define        RXH_XFRM_NO_CHANGE      0xff
 
-/* L2-L4 network traffic flow types */
-#define        TCP_V4_FLOW     0x01    /* hash or spec (tcp_ip4_spec) */
-#define        UDP_V4_FLOW     0x02    /* hash or spec (udp_ip4_spec) */
-#define        SCTP_V4_FLOW    0x03    /* hash or spec (sctp_ip4_spec) */
-#define        AH_ESP_V4_FLOW  0x04    /* hash only */
-#define        TCP_V6_FLOW     0x05    /* hash or spec (tcp_ip6_spec; nfc only) */
-#define        UDP_V6_FLOW     0x06    /* hash or spec (udp_ip6_spec; nfc only) */
-#define        SCTP_V6_FLOW    0x07    /* hash or spec (sctp_ip6_spec; nfc only) */
-#define        AH_ESP_V6_FLOW  0x08    /* hash only */
-#define        AH_V4_FLOW      0x09    /* hash or spec (ah_ip4_spec) */
-#define        ESP_V4_FLOW     0x0a    /* hash or spec (esp_ip4_spec) */
-#define        AH_V6_FLOW      0x0b    /* hash or spec (ah_ip6_spec; nfc only) */
-#define        ESP_V6_FLOW     0x0c    /* hash or spec (esp_ip6_spec; nfc only) */
-#define        IPV4_USER_FLOW  0x0d    /* spec only (usr_ip4_spec) */
-#define        IP_USER_FLOW    IPV4_USER_FLOW
-#define        IPV6_USER_FLOW  0x0e    /* spec only (usr_ip6_spec; nfc only) */
-#define        IPV4_FLOW       0x10    /* hash only */
-#define        IPV6_FLOW       0x11    /* hash only */
-#define        ETHER_FLOW      0x12    /* spec only (ether_spec) */
-
-/* Used for GTP-U IPv4 and IPv6.
- * The format of GTP packets only includes
- * elements such as TEID and GTP version.
- * It is primarily intended for data communication of the UE.
- */
-#define GTPU_V4_FLOW 0x13      /* hash only */
-#define GTPU_V6_FLOW 0x14      /* hash only */
-
-/* Use for GTP-C IPv4 and v6.
- * The format of these GTP packets does not include TEID.
- * Primarily expected to be used for communication
- * to create sessions for UE data communication,
- * commonly referred to as CSR (Create Session Request).
- */
-#define GTPC_V4_FLOW 0x15      /* hash only */
-#define GTPC_V6_FLOW 0x16      /* hash only */
-
-/* Use for GTP-C IPv4 and v6.
- * Unlike GTPC_V4_FLOW, the format of these GTP packets includes TEID.
- * After session creation, it becomes this packet.
- * This is mainly used for requests to realize UE handover.
- */
-#define GTPC_TEID_V4_FLOW 0x17 /* hash only */
-#define GTPC_TEID_V6_FLOW 0x18 /* hash only */
-
-/* Use for GTP-U and extended headers for the PSC (PDU Session Container).
- * The format of these GTP packets includes TEID and QFI.
- * In 5G communication using UPF (User Plane Function),
- * data communication with this extended header is performed.
- */
-#define GTPU_EH_V4_FLOW 0x19   /* hash only */
-#define GTPU_EH_V6_FLOW 0x1a   /* hash only */
-
-/* Use for GTP-U IPv4 and v6 PSC (PDU Session Container) extended headers.
- * This differs from GTPU_EH_V(4|6)_FLOW in that it is distinguished by
- * UL/DL included in the PSC.
- * There are differences in the data included based on Downlink/Uplink,
- * and can be used to distinguish packets.
- * The functions described so far are useful when you want to
- * handle communication from the mobile network in UPF, PGW, etc.
- */
-#define GTPU_UL_V4_FLOW 0x1b   /* hash only */
-#define GTPU_UL_V6_FLOW 0x1c   /* hash only */
-#define GTPU_DL_V4_FLOW 0x1d   /* hash only */
-#define GTPU_DL_V6_FLOW 0x1e   /* hash only */
+enum {
+       /* L2-L4 network traffic flow types */
+       TCP_V4_FLOW     = 0x01, /* hash or spec (tcp_ip4_spec) */
+       UDP_V4_FLOW     = 0x02, /* hash or spec (udp_ip4_spec) */
+       SCTP_V4_FLOW    = 0x03, /* hash or spec (sctp_ip4_spec) */
+       AH_ESP_V4_FLOW  = 0x04, /* hash only */
+       TCP_V6_FLOW     = 0x05, /* hash or spec (tcp_ip6_spec; nfc only) */
+       UDP_V6_FLOW     = 0x06, /* hash or spec (udp_ip6_spec; nfc only) */
+       SCTP_V6_FLOW    = 0x07, /* hash or spec (sctp_ip6_spec; nfc only) */
+       AH_ESP_V6_FLOW  = 0x08, /* hash only */
+       AH_V4_FLOW      = 0x09, /* hash or spec (ah_ip4_spec) */
+       ESP_V4_FLOW     = 0x0a, /* hash or spec (esp_ip4_spec) */
+       AH_V6_FLOW      = 0x0b, /* hash or spec (ah_ip6_spec; nfc only) */
+       ESP_V6_FLOW     = 0x0c, /* hash or spec (esp_ip6_spec; nfc only) */
+       IPV4_USER_FLOW  = 0x0d, /* spec only (usr_ip4_spec) */
+       IP_USER_FLOW    = IPV4_USER_FLOW,
+       IPV6_USER_FLOW  = 0x0e, /* spec only (usr_ip6_spec; nfc only) */
+       IPV4_FLOW       = 0x10, /* hash only */
+       IPV6_FLOW       = 0x11, /* hash only */
+       ETHER_FLOW      = 0x12, /* spec only (ether_spec) */
+
+       /* Used for GTP-U IPv4 and IPv6.
+        * The format of GTP packets only includes
+        * elements such as TEID and GTP version.
+        * It is primarily intended for data communication of the UE.
+        */
+       GTPU_V4_FLOW    = 0x13, /* hash only */
+       GTPU_V6_FLOW    = 0x14, /* hash only */
+
+       /* Use for GTP-C IPv4 and v6.
+        * The format of these GTP packets does not include TEID.
+        * Primarily expected to be used for communication
+        * to create sessions for UE data communication,
+        * commonly referred to as CSR (Create Session Request).
+        */
+       GTPC_V4_FLOW    = 0x15, /* hash only */
+       GTPC_V6_FLOW    = 0x16, /* hash only */
+
+       /* Use for GTP-C IPv4 and v6.
+        * Unlike GTPC_V4_FLOW, the format of these GTP packets includes TEID.
+        * After session creation, it becomes this packet.
+        * This is mainly used for requests to realize UE handover.
+        */
+       GTPC_TEID_V4_FLOW       = 0x17, /* hash only */
+       GTPC_TEID_V6_FLOW       = 0x18, /* hash only */
+
+       /* Use for GTP-U and extended headers for the PSC (PDU Session Container).
+        * The format of these GTP packets includes TEID and QFI.
+        * In 5G communication using UPF (User Plane Function),
+        * data communication with this extended header is performed.
+        */
+       GTPU_EH_V4_FLOW = 0x19, /* hash only */
+       GTPU_EH_V6_FLOW = 0x1a, /* hash only */
+
+       /* Use for GTP-U IPv4 and v6 PSC (PDU Session Container) extended headers.
+        * This differs from GTPU_EH_V(4|6)_FLOW in that it is distinguished by
+        * UL/DL included in the PSC.
+        * There are differences in the data included based on Downlink/Uplink,
+        * and can be used to distinguish packets.
+        * The functions described so far are useful when you want to
+        * handle communication from the mobile network in UPF, PGW, etc.
+        */
+       GTPU_UL_V4_FLOW = 0x1b, /* hash only */
+       GTPU_UL_V6_FLOW = 0x1c, /* hash only */
+       GTPU_DL_V4_FLOW = 0x1d, /* hash only */
+       GTPU_DL_V6_FLOW = 0x1e, /* hash only */
+
+       __FLOW_TYPE_COUNT,
+};
 
 /* Flag to enable additional fields in struct ethtool_rx_flow_spec */
 #define        FLOW_EXT        0x80000000

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 8262cc10f98db77ba29c68afc5f2deda716dba08..39ec920f5de72c151e2f526d6ffafbfc07d7b036 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -978,6 +978,88 @@ static int ethtool_rxnfc_copy_to_user(void __user *useraddr,
        return 0;
 }
 
+static bool flow_type_hashable(u32 flow_type)
+{
+       switch (flow_type) {
+       case TCP_V4_FLOW:
+       case UDP_V4_FLOW:
+       case SCTP_V4_FLOW:
+       case AH_ESP_V4_FLOW:
+       case TCP_V6_FLOW:
+       case UDP_V6_FLOW:
+       case SCTP_V6_FLOW:
+       case AH_ESP_V6_FLOW:
+       case AH_V4_FLOW:
+       case ESP_V4_FLOW:
+       case AH_V6_FLOW:
+       case ESP_V6_FLOW:
+       case IPV4_FLOW:
+       case IPV6_FLOW:
+       case GTPU_V4_FLOW:
+       case GTPU_V6_FLOW:
+       case GTPC_V4_FLOW:
+       case GTPC_V6_FLOW:
+       case GTPC_TEID_V4_FLOW:
+       case GTPC_TEID_V6_FLOW:
+       case GTPU_EH_V4_FLOW:
+       case GTPU_EH_V6_FLOW:
+       case GTPU_UL_V4_FLOW:
+       case GTPU_UL_V6_FLOW:
+       case GTPU_DL_V4_FLOW:
+       case GTPU_DL_V6_FLOW:
+               return true;
+       }
+
+       return false;
+}
+
+/* When adding a new type, update the assert and, if it's hashable, add it to
+ * the flow_type_hashable switch case.
+ */
+static_assert(GTPU_DL_V6_FLOW + 1 == __FLOW_TYPE_COUNT);
+
+static int ethtool_check_xfrm_rxfh(u32 input_xfrm, u64 rxfh)
+{
+       /* Sanity check: if symmetric-xor/symmetric-or-xor is set, then:
+        * 1 - no other fields besides IP src/dst and/or L4 src/dst are set
+        * 2 - If src is set, dst must also be set
+        */
+       if ((input_xfrm != RXH_XFRM_NO_CHANGE &&
+            input_xfrm & (RXH_XFRM_SYM_XOR | RXH_XFRM_SYM_OR_XOR)) &&
+           ((rxfh & ~(RXH_IP_SRC | RXH_IP_DST | RXH_L4_B_0_1 | RXH_L4_B_2_3)) ||
+            (!!(rxfh & RXH_IP_SRC) ^ !!(rxfh & RXH_IP_DST)) ||
+            (!!(rxfh & RXH_L4_B_0_1) ^ !!(rxfh & RXH_L4_B_2_3))))
+               return -EINVAL;
+
+       return 0;
+}
+
+static int ethtool_check_flow_types(struct net_device *dev, u32 input_xfrm)
+{
+       const struct ethtool_ops *ops = dev->ethtool_ops;
+       struct ethtool_rxnfc info = {
+               .cmd = ETHTOOL_GRXFH,
+       };
+       int err;
+       u32 i;
+
+       for (i = 0; i < __FLOW_TYPE_COUNT; i++) {
+               if (!flow_type_hashable(i))
+                       continue;
+
+               info.flow_type = i;
+               err = ops->get_rxnfc(dev, &info, NULL);
+               if (err)
+                       continue;
+
+               err = ethtool_check_xfrm_rxfh(input_xfrm, info.data);
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}
+
 static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
                                                u32 cmd, void __user *useraddr)
 {
@@ -1012,16 +1094,9 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
                if (rc)
                        return rc;
 
-               /* Sanity check: if symmetric-xor/symmetric-or-xor is set, then:
-                * 1 - no other fields besides IP src/dst and/or L4 src/dst
-                * 2 - If src is set, dst must also be set
-                */
-               if ((rxfh.input_xfrm & (RXH_XFRM_SYM_XOR | RXH_XFRM_SYM_OR_XOR)) &&
-                   ((info.data & ~(RXH_IP_SRC | RXH_IP_DST |
-                                   RXH_L4_B_0_1 | RXH_L4_B_2_3)) ||
-                    (!!(info.data & RXH_IP_SRC) ^ !!(info.data & RXH_IP_DST)) ||
-                    (!!(info.data & RXH_L4_B_0_1) ^ !!(info.data & RXH_L4_B_2_3))))
-                       return -EINVAL;
+               rc = ethtool_check_xfrm_rxfh(rxfh.input_xfrm, info.data);
+               if (rc)
+                       return rc;
        }
 
        rc = ops->set_rxnfc(dev, &info);
@@ -1413,6 +1488,10 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
             rxfh.input_xfrm == RXH_XFRM_NO_CHANGE))
                return -EINVAL;
 
+       ret = ethtool_check_flow_types(dev, rxfh.input_xfrm);
+       if (ret)
+               return ret;
+
        indir_bytes = dev_indir_size * sizeof(rxfh_dev.indir[0]);
 
        /* Check settings which may be global rather than per RSS-context */