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authorEric Dumazet <edumazet@google.com>2023-06-08 22:17:37 +0300
committerJakub Kicinski <kuba@kernel.org>2023-06-10 10:11:41 +0300
commitd457a0e329b0bfd3a1450e0b1a18cd2b47a25a08 (patch)
treeeafa7a6c0d45e727a9eb25c6a4cc5dd8b4652217 /net/core/gso.c
parentcabb8b48e542e1401f6881c4f7d3bb82f723ee40 (diff)
downloadlinux-d457a0e329b0bfd3a1450e0b1a18cd2b47a25a08.tar.xz
net: move gso declarations and functions to their own files
Move declarations into include/net/gso.h and code into net/core/gso.c Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Stanislav Fomichev <sdf@google.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core/gso.c')
-rw-r--r--net/core/gso.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/net/core/gso.c b/net/core/gso.c
new file mode 100644
index 000000000000..9e1803bfc9c6
--- /dev/null
+++ b/net/core/gso.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/skbuff.h>
+#include <linux/sctp.h>
+#include <net/gso.h>
+#include <net/gro.h>
+
+/**
+ * skb_eth_gso_segment - segmentation handler for ethernet protocols.
+ * @skb: buffer to segment
+ * @features: features for the output path (see dev->features)
+ * @type: Ethernet Protocol ID
+ */
+struct sk_buff *skb_eth_gso_segment(struct sk_buff *skb,
+ netdev_features_t features, __be16 type)
+{
+ struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
+ struct packet_offload *ptype;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ptype, &offload_base, list) {
+ if (ptype->type == type && ptype->callbacks.gso_segment) {
+ segs = ptype->callbacks.gso_segment(skb, features);
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return segs;
+}
+EXPORT_SYMBOL(skb_eth_gso_segment);
+
+/**
+ * skb_mac_gso_segment - mac layer segmentation handler.
+ * @skb: buffer to segment
+ * @features: features for the output path (see dev->features)
+ */
+struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
+ struct packet_offload *ptype;
+ int vlan_depth = skb->mac_len;
+ __be16 type = skb_network_protocol(skb, &vlan_depth);
+
+ if (unlikely(!type))
+ return ERR_PTR(-EINVAL);
+
+ __skb_pull(skb, vlan_depth);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ptype, &offload_base, list) {
+ if (ptype->type == type && ptype->callbacks.gso_segment) {
+ segs = ptype->callbacks.gso_segment(skb, features);
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ __skb_push(skb, skb->data - skb_mac_header(skb));
+
+ return segs;
+}
+EXPORT_SYMBOL(skb_mac_gso_segment);
+/* openvswitch calls this on rx path, so we need a different check.
+ */
+static bool skb_needs_check(const struct sk_buff *skb, bool tx_path)
+{
+ if (tx_path)
+ return skb->ip_summed != CHECKSUM_PARTIAL &&
+ skb->ip_summed != CHECKSUM_UNNECESSARY;
+
+ return skb->ip_summed == CHECKSUM_NONE;
+}
+
+/**
+ * __skb_gso_segment - Perform segmentation on skb.
+ * @skb: buffer to segment
+ * @features: features for the output path (see dev->features)
+ * @tx_path: whether it is called in TX path
+ *
+ * This function segments the given skb and returns a list of segments.
+ *
+ * It may return NULL if the skb requires no segmentation. This is
+ * only possible when GSO is used for verifying header integrity.
+ *
+ * Segmentation preserves SKB_GSO_CB_OFFSET bytes of previous skb cb.
+ */
+struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
+ netdev_features_t features, bool tx_path)
+{
+ struct sk_buff *segs;
+
+ if (unlikely(skb_needs_check(skb, tx_path))) {
+ int err;
+
+ /* We're going to init ->check field in TCP or UDP header */
+ err = skb_cow_head(skb, 0);
+ if (err < 0)
+ return ERR_PTR(err);
+ }
+
+ /* Only report GSO partial support if it will enable us to
+ * support segmentation on this frame without needing additional
+ * work.
+ */
+ if (features & NETIF_F_GSO_PARTIAL) {
+ netdev_features_t partial_features = NETIF_F_GSO_ROBUST;
+ struct net_device *dev = skb->dev;
+
+ partial_features |= dev->features & dev->gso_partial_features;
+ if (!skb_gso_ok(skb, features | partial_features))
+ features &= ~NETIF_F_GSO_PARTIAL;
+ }
+
+ BUILD_BUG_ON(SKB_GSO_CB_OFFSET +
+ sizeof(*SKB_GSO_CB(skb)) > sizeof(skb->cb));
+
+ SKB_GSO_CB(skb)->mac_offset = skb_headroom(skb);
+ SKB_GSO_CB(skb)->encap_level = 0;
+
+ skb_reset_mac_header(skb);
+ skb_reset_mac_len(skb);
+
+ segs = skb_mac_gso_segment(skb, features);
+
+ if (segs != skb && unlikely(skb_needs_check(skb, tx_path) && !IS_ERR(segs)))
+ skb_warn_bad_offload(skb);
+
+ return segs;
+}
+EXPORT_SYMBOL(__skb_gso_segment);
+
+/**
+ * skb_gso_transport_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_transport_seglen is used to determine the real size of the
+ * individual segments, including Layer4 headers (TCP/UDP).
+ *
+ * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
+ */
+static unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
+{
+ const struct skb_shared_info *shinfo = skb_shinfo(skb);
+ unsigned int thlen = 0;
+
+ if (skb->encapsulation) {
+ thlen = skb_inner_transport_header(skb) -
+ skb_transport_header(skb);
+
+ if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
+ thlen += inner_tcp_hdrlen(skb);
+ } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
+ thlen = tcp_hdrlen(skb);
+ } else if (unlikely(skb_is_gso_sctp(skb))) {
+ thlen = sizeof(struct sctphdr);
+ } else if (shinfo->gso_type & SKB_GSO_UDP_L4) {
+ thlen = sizeof(struct udphdr);
+ }
+ /* UFO sets gso_size to the size of the fragmentation
+ * payload, i.e. the size of the L4 (UDP) header is already
+ * accounted for.
+ */
+ return thlen + shinfo->gso_size;
+}
+
+/**
+ * skb_gso_network_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_network_seglen is used to determine the real size of the
+ * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
+ *
+ * The MAC/L2 header is not accounted for.
+ */
+static unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
+{
+ unsigned int hdr_len = skb_transport_header(skb) -
+ skb_network_header(skb);
+
+ return hdr_len + skb_gso_transport_seglen(skb);
+}
+
+/**
+ * skb_gso_mac_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_mac_seglen is used to determine the real size of the
+ * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4
+ * headers (TCP/UDP).
+ */
+static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
+{
+ unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
+
+ return hdr_len + skb_gso_transport_seglen(skb);
+}
+
+/**
+ * skb_gso_size_check - check the skb size, considering GSO_BY_FRAGS
+ *
+ * There are a couple of instances where we have a GSO skb, and we
+ * want to determine what size it would be after it is segmented.
+ *
+ * We might want to check:
+ * - L3+L4+payload size (e.g. IP forwarding)
+ * - L2+L3+L4+payload size (e.g. sanity check before passing to driver)
+ *
+ * This is a helper to do that correctly considering GSO_BY_FRAGS.
+ *
+ * @skb: GSO skb
+ *
+ * @seg_len: The segmented length (from skb_gso_*_seglen). In the
+ * GSO_BY_FRAGS case this will be [header sizes + GSO_BY_FRAGS].
+ *
+ * @max_len: The maximum permissible length.
+ *
+ * Returns true if the segmented length <= max length.
+ */
+static inline bool skb_gso_size_check(const struct sk_buff *skb,
+ unsigned int seg_len,
+ unsigned int max_len) {
+ const struct skb_shared_info *shinfo = skb_shinfo(skb);
+ const struct sk_buff *iter;
+
+ if (shinfo->gso_size != GSO_BY_FRAGS)
+ return seg_len <= max_len;
+
+ /* Undo this so we can re-use header sizes */
+ seg_len -= GSO_BY_FRAGS;
+
+ skb_walk_frags(skb, iter) {
+ if (seg_len + skb_headlen(iter) > max_len)
+ return false;
+ }
+
+ return true;
+}
+
+/**
+ * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU?
+ *
+ * @skb: GSO skb
+ * @mtu: MTU to validate against
+ *
+ * skb_gso_validate_network_len validates if a given skb will fit a
+ * wanted MTU once split. It considers L3 headers, L4 headers, and the
+ * payload.
+ */
+bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu)
+{
+ return skb_gso_size_check(skb, skb_gso_network_seglen(skb), mtu);
+}
+EXPORT_SYMBOL_GPL(skb_gso_validate_network_len);
+
+/**
+ * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?
+ *
+ * @skb: GSO skb
+ * @len: length to validate against
+ *
+ * skb_gso_validate_mac_len validates if a given skb will fit a wanted
+ * length once split, including L2, L3 and L4 headers and the payload.
+ */
+bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len)
+{
+ return skb_gso_size_check(skb, skb_gso_mac_seglen(skb), len);
+}
+EXPORT_SYMBOL_GPL(skb_gso_validate_mac_len);
+