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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /include/net/udplite.h
Initial import
Diffstat (limited to 'include/net/udplite.h')
-rw-r--r--include/net/udplite.h133
1 files changed, 133 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 000000000..80761938b
--- /dev/null
+++ b/include/net/udplite.h
@@ -0,0 +1,133 @@
+/*
+ * Definitions for the UDP-Lite (RFC 3828) code.
+ */
+#ifndef _UDPLITE_H
+#define _UDPLITE_H
+
+#include <net/ip6_checksum.h>
+
+/* UDP-Lite socket options */
+#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
+#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
+
+extern struct proto udplite_prot;
+extern struct udp_table udplite_table;
+
+/*
+ * Checksum computation is all in software, hence simpler getfrag.
+ */
+static __inline__ int udplite_getfrag(void *from, char *to, int offset,
+ int len, int odd, struct sk_buff *skb)
+{
+ struct msghdr *msg = from;
+ return copy_from_iter(to, len, &msg->msg_iter) != len ? -EFAULT : 0;
+}
+
+/* Designate sk as UDP-Lite socket */
+static inline int udplite_sk_init(struct sock *sk)
+{
+ udp_sk(sk)->pcflag = UDPLITE_BIT;
+ return 0;
+}
+
+/*
+ * Checksumming routines
+ */
+static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+ u16 cscov;
+
+ /* In UDPv4 a zero checksum means that the transmitter generated no
+ * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
+ * with a zero checksum field are illegal. */
+ if (uh->check == 0) {
+ net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
+ return 1;
+ }
+
+ cscov = ntohs(uh->len);
+
+ if (cscov == 0) /* Indicates that full coverage is required. */
+ ;
+ else if (cscov < 8 || cscov > skb->len) {
+ /*
+ * Coverage length violates RFC 3828: log and discard silently.
+ */
+ net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
+ cscov, skb->len);
+ return 1;
+
+ } else if (cscov < skb->len) {
+ UDP_SKB_CB(skb)->partial_cov = 1;
+ UDP_SKB_CB(skb)->cscov = cscov;
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+
+ return 0;
+}
+
+/* Slow-path computation of checksum. Socket is locked. */
+static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
+{
+ const struct udp_sock *up = udp_sk(skb->sk);
+ int cscov = up->len;
+ __wsum csum = 0;
+
+ if (up->pcflag & UDPLITE_SEND_CC) {
+ /*
+ * Sender has set `partial coverage' option on UDP-Lite socket.
+ * The special case "up->pcslen == 0" signifies full coverage.
+ */
+ if (up->pcslen < up->len) {
+ if (0 < up->pcslen)
+ cscov = up->pcslen;
+ udp_hdr(skb)->len = htons(up->pcslen);
+ }
+ /*
+ * NOTE: Causes for the error case `up->pcslen > up->len':
+ * (i) Application error (will not be penalized).
+ * (ii) Payload too big for send buffer: data is split
+ * into several packets, each with its own header.
+ * In this case (e.g. last segment), coverage may
+ * exceed packet length.
+ * Since packets with coverage length > packet length are
+ * illegal, we fall back to the defaults here.
+ */
+ }
+
+ skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
+
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ const int off = skb_transport_offset(skb);
+ const int len = skb->len - off;
+
+ csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
+
+ if ((cscov -= len) <= 0)
+ break;
+ }
+ return csum;
+}
+
+/* Fast-path computation of checksum. Socket may not be locked. */
+static inline __wsum udplite_csum(struct sk_buff *skb)
+{
+ const struct udp_sock *up = udp_sk(skb->sk);
+ const int off = skb_transport_offset(skb);
+ int len = skb->len - off;
+
+ if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
+ if (0 < up->pcslen)
+ len = up->pcslen;
+ udp_hdr(skb)->len = htons(up->pcslen);
+ }
+ skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
+
+ return skb_checksum(skb, off, len, 0);
+}
+
+void udplite4_register(void);
+int udplite_get_port(struct sock *sk, unsigned short snum,
+ int (*scmp)(const struct sock *, const struct sock *));
+#endif /* _UDPLITE_H */