initial version by sklower

SCCS-vsn: sys/net/if_dl.h 7.1

diff --git a/usr/src/sys/net/if_dl.h b/usr/src/sys/net/if_dl.h
new file mode 100644 (file)
index 0000000..561df44
--- /dev/null
+++ b/usr/src/sys/net/if_dl.h
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+/*
+ * Copyright (c) 1990 Regents of the University of California.
+ * All rights reserved.
+ *
+ * %sccs.include.redist.c%
+ *
+ *     @(#)if_dl.h     7.1 (Berkeley) %G%
+ */
+
+/* 
+ * A Link-Level Sockaddr may specify the interface in one of two
+ * ways: either by means of a system-provided index number (computed
+ * anew and possibly differently on every reboot), or by a human-readable
+ * string such as "il0" (for managerial convenience).
+ * 
+ * Census taking actions, such as something akin to SIOCGCONF would return
+ * both the index and the human name.
+ * 
+ * High volume transactions (such as giving a link-level ``from'' address
+ * in a recvfrom or recvmsg call) may be likely only to provide the indexed
+ * form, (which requires fewer copy operations and less space).
+ * 
+ * The form and interpretation  of the link-level address is purely a matter
+ * of convention between the device driver and its consumers; however, it is
+ * expected that all drivers for an interface of a given if_type will agree.
+ */
+
+/*
+ * Structure of a Link-Level sockaddr:
+ */
+struct sockaddr_dl {
+       u_char  sdl_len;        /* Total length of sockaddr */
+       u_char  sdl_family;     /* AF_DLI */
+       u_short sdl_index;      /* if != 0, system given index for interface */
+       u_char  sdl_type;       /* interface type */
+       u_char  sdl_nlen;       /* interface name length, no trailing 0 reqd. */
+       u_char  sdl_alen;       /* link level address length */
+       u_char  sdl_slen;       /* link layer selector length */
+       char    sdl_data[12];   /* minimum work area, can be larger;
+                                  contains both if name and ll address */
+};
+
+#define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
+