1 files changed, 371 insertions, 0 deletions

diff --git a/src/lib/libc/net/ip6opt.c b/src/lib/libc/net/ip6opt.c
new file mode 100644
index 0000000000..565c0ed369
--- /dev/null
+++ b/src/lib/libc/net/ip6opt.c
@@ -0,0 +1,371 @@
+/*      $OpenBSD: ip6opt.c,v 1.2 2005/03/25 13:24:12 otto Exp $ */
+
+/*
+ * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+#include <netinet/ip6.h>
+
+#include <string.h>
+#include <stdio.h>
+
+static int ip6optlen(u_int8_t *opt, u_int8_t *lim);
+static void inet6_insert_padopt(u_char *p, int len);
+
+/*
+ * This function returns the number of bytes required to hold an option
+ * when it is stored as ancillary data, including the cmsghdr structure
+ * at the beginning, and any padding at the end (to make its size a
+ * multiple of 8 bytes).  The argument is the size of the structure
+ * defining the option, which must include any pad bytes at the
+ * beginning (the value y in the alignment term "xn + y"), the type
+ * byte, the length byte, and the option data.
+ */
+int
+inet6_option_space(int nbytes)
+{
+        nbytes += 2;    /* we need space for nxt-hdr and length fields */
+        return(CMSG_SPACE((nbytes + 7) & ~7));
+}
+
+/*
+ * This function is called once per ancillary data object that will
+ * contain either Hop-by-Hop or Destination options.  It returns 0 on
+ * success or -1 on an error.
+ */
+int
+inet6_option_init(void *bp, struct cmsghdr **cmsgp, int type)
+{
+        struct cmsghdr *ch = (struct cmsghdr *)bp;
+
+        /* argument validation */
+        if (type != IPV6_HOPOPTS && type != IPV6_DSTOPTS)
+                return(-1);
+        
+        ch->cmsg_level = IPPROTO_IPV6;
+        ch->cmsg_type = type;
+        ch->cmsg_len = CMSG_LEN(0);
+
+        *cmsgp = ch;
+        return(0);
+}
+
+/*
+ * This function appends a Hop-by-Hop option or a Destination option
+ * into an ancillary data object that has been initialized by
+ * inet6_option_init().  This function returns 0 if it succeeds or -1 on
+ * an error.
+ * multx is the value x in the alignment term "xn + y" described
+ * earlier.  It must have a value of 1, 2, 4, or 8.
+ * plusy is the value y in the alignment term "xn + y" described
+ * earlier.  It must have a value between 0 and 7, inclusive.
+ */
+int
+inet6_option_append(struct cmsghdr *cmsg, const u_int8_t *typep, int multx,
+    int plusy)
+{
+        int padlen, optlen, off;
+        u_char *bp = (u_char *)cmsg + cmsg->cmsg_len;
+        struct ip6_ext *eh = (struct ip6_ext *)CMSG_DATA(cmsg);
+
+        /* argument validation */
+        if (multx != 1 && multx != 2 && multx != 4 && multx != 8)
+                return(-1);
+        if (plusy < 0 || plusy > 7)
+                return(-1);
+        if (typep[0] > 255)
+                return(-1);
+
+        /*
+         * If this is the first option, allocate space for the
+         * first 2 bytes(for next header and length fields) of
+         * the option header.
+         */
+        if (bp == (u_char *)eh) {
+                bp += 2;
+                cmsg->cmsg_len += 2;
+        }
+
+        /* calculate pad length before the option. */
+        off = bp - (u_char *)eh;
+        padlen = (((off % multx) + (multx - 1)) & ~(multx - 1)) -
+                (off % multx);
+        padlen += plusy;
+        padlen %= multx;        /* keep the pad as short as possible */
+        /* insert padding */
+        inet6_insert_padopt(bp, padlen);
+        cmsg->cmsg_len += padlen;
+        bp += padlen;
+
+        /* copy the option */
+        if (typep[0] == IP6OPT_PAD1)
+                optlen = 1;
+        else
+                optlen = typep[1] + 2;
+        memcpy(bp, typep, optlen);
+        bp += optlen;
+        cmsg->cmsg_len += optlen;
+
+        /* calculate pad length after the option and insert the padding */
+        off = bp - (u_char *)eh;
+        padlen = ((off + 7) & ~7) - off;
+        inet6_insert_padopt(bp, padlen);
+        bp += padlen;
+        cmsg->cmsg_len += padlen;
+
+        /* update the length field of the ip6 option header */
+        eh->ip6e_len = ((bp - (u_char *)eh) >> 3) - 1;
+
+        return(0);
+}
+
+/*
+ * This function appends a Hop-by-Hop option or a Destination option
+ * into an ancillary data object that has been initialized by
+ * inet6_option_init().  This function returns a pointer to the 8-bit
+ * option type field that starts the option on success, or NULL on an
+ * error.
+ * The difference between this function and inet6_option_append() is
+ * that the latter copies the contents of a previously built option into
+ * the ancillary data object while the current function returns a
+ * pointer to the space in the data object where the option's TLV must
+ * then be built by the caller.
+ * 
+ */
+u_int8_t *
+inet6_option_alloc(struct cmsghdr *cmsg, int datalen, int multx, int plusy)
+{
+        int padlen, off;
+        u_int8_t *bp = (u_char *)cmsg + cmsg->cmsg_len;
+        u_int8_t *retval;
+        struct ip6_ext *eh = (struct ip6_ext *)CMSG_DATA(cmsg);
+
+        /* argument validation */
+        if (multx != 1 && multx != 2 && multx != 4 && multx != 8)
+                return(NULL);
+        if (plusy < 0 || plusy > 7)
+                return(NULL);
+
+        /*
+         * If this is the first option, allocate space for the
+         * first 2 bytes(for next header and length fields) of
+         * the option header.
+         */
+        if (bp == (u_char *)eh) {
+                bp += 2;
+                cmsg->cmsg_len += 2;
+        }
+
+        /* calculate pad length before the option. */
+        off = bp - (u_char *)eh;
+        padlen = (((off % multx) + (multx - 1)) & ~(multx - 1)) -
+                (off % multx);
+        padlen += plusy;
+        padlen %= multx;        /* keep the pad as short as possible */
+        /* insert padding */
+        inet6_insert_padopt(bp, padlen);
+        cmsg->cmsg_len += padlen;
+        bp += padlen;
+
+        /* keep space to store specified length of data */
+        retval = bp;
+        bp += datalen;
+        cmsg->cmsg_len += datalen;
+
+        /* calculate pad length after the option and insert the padding */
+        off = bp - (u_char *)eh;
+        padlen = ((off + 7) & ~7) - off;
+        inet6_insert_padopt(bp, padlen);
+        bp += padlen;
+        cmsg->cmsg_len += padlen;
+
+        /* update the length field of the ip6 option header */
+        eh->ip6e_len = ((bp - (u_char *)eh) >> 3) - 1;
+
+        return(retval);
+}
+
+/*
+ * This function processes the next Hop-by-Hop option or Destination
+ * option in an ancillary data object.  If another option remains to be
+ * processed, the return value of the function is 0 and *tptrp points to
+ * the 8-bit option type field (which is followed by the 8-bit option
+ * data length, followed by the option data).  If no more options remain
+ * to be processed, the return value is -1 and *tptrp is NULL.  If an
+ * error occurs, the return value is -1 and *tptrp is not NULL.
+ * (RFC 2292, 6.3.5)
+ */
+int
+inet6_option_next(const struct cmsghdr *cmsg, u_int8_t **tptrp)
+{
+        struct ip6_ext *ip6e;
+        int hdrlen, optlen;
+        u_int8_t *lim;
+
+        if (cmsg->cmsg_level != IPPROTO_IPV6 ||
+            (cmsg->cmsg_type != IPV6_HOPOPTS &&
+             cmsg->cmsg_type != IPV6_DSTOPTS))
+                return(-1);
+
+        /* message length validation */
+        if (cmsg->cmsg_len < CMSG_SPACE(sizeof(struct ip6_ext)))
+                return(-1);
+        ip6e = (struct ip6_ext *)CMSG_DATA(cmsg);
+        hdrlen = (ip6e->ip6e_len + 1) << 3;
+        if (cmsg->cmsg_len < CMSG_SPACE(hdrlen))
+                return(-1);
+
+        /*
+         * If the caller does not specify the starting point,
+         * simply return the 1st option.
+         * Otherwise, search the option list for the next option.
+         */
+        lim = (u_int8_t *)ip6e + hdrlen;
+        if (*tptrp == NULL)
+                *tptrp = (u_int8_t *)(ip6e + 1);
+        else {
+                if ((optlen = ip6optlen(*tptrp, lim)) == 0)
+                        return(-1);
+
+                *tptrp = *tptrp + optlen;
+        }
+        if (*tptrp >= lim) {    /* there is no option */
+                *tptrp = NULL;
+                return(-1);
+        }
+        /*
+         * Finally, checks if the next option is safely stored in the
+         * cmsg data.
+         */
+        if (ip6optlen(*tptrp, lim) == 0)
+                return(-1);
+        else
+                return(0);
+}
+
+/*
+ * This function is similar to the inet6_option_next() function,
+ * except this function lets the caller specify the option type to be
+ * searched for, instead of always returning the next option in the
+ * ancillary data object.
+ * Note: RFC 2292 says the type of tptrp is u_int8_t *, but we think
+ *       it's a typo. The variable should be type of u_int8_t **.
+ */
+int
+inet6_option_find(const struct cmsghdr *cmsg, u_int8_t **tptrp, int type)
+{
+        struct ip6_ext *ip6e;
+        int hdrlen, optlen;
+        u_int8_t *optp, *lim;
+
+        if (cmsg->cmsg_level != IPPROTO_IPV6 ||
+            (cmsg->cmsg_type != IPV6_HOPOPTS &&
+             cmsg->cmsg_type != IPV6_DSTOPTS))
+                return(-1);
+
+        /* message length validation */
+        if (cmsg->cmsg_len < CMSG_SPACE(sizeof(struct ip6_ext)))
+                return(-1);
+        ip6e = (struct ip6_ext *)CMSG_DATA(cmsg);
+        hdrlen = (ip6e->ip6e_len + 1) << 3;
+        if (cmsg->cmsg_len < CMSG_SPACE(hdrlen))
+                return(-1);     
+
+        /*
+         * If the caller does not specify the starting point,
+         * search from the beginning of the option list.
+         * Otherwise, search from *the next option* of the specified point.
+         */
+        lim = (u_int8_t *)ip6e + hdrlen;
+        if (*tptrp == NULL)
+                *tptrp = (u_int8_t *)(ip6e + 1);
+        else {
+                if ((optlen = ip6optlen(*tptrp, lim)) == 0)
+                        return(-1);
+
+                *tptrp = *tptrp + optlen;
+        }
+        for (optp = *tptrp; optp < lim; optp += optlen) {
+                if (*optp == type) {
+                        *tptrp = optp;
+                        return(0);
+                }
+                if ((optlen = ip6optlen(optp, lim)) == 0)
+                        return(-1);
+        }
+
+        /* search failed */
+        *tptrp = NULL;
+        return(-1);
+}
+
+/*
+ * Calculate the length of a given IPv6 option. Also checks
+ * if the option is safely stored in user's buffer according to the
+ * calculated length and the limitation of the buffer.
+ */
+static int
+ip6optlen(u_int8_t *opt, u_int8_t *lim)
+{
+        int optlen;
+
+        if (*opt == IP6OPT_PAD1)
+                optlen = 1;
+        else {
+                /* is there enough space to store type and len? */
+                if (opt + 2 > lim)
+                        return(0);
+                optlen = *(opt + 1) + 2;
+        }
+        if (opt + optlen <= lim)
+                return(optlen);
+
+        return(0);
+}
+
+static void
+inet6_insert_padopt(u_char *p, int len)
+{
+        switch(len) {
+         case 0:
+                 return;
+         case 1:
+                 p[0] = IP6OPT_PAD1;
+                 return;
+         default:
+                 p[0] = IP6OPT_PADN;
+                 p[1] = len - 2; 
+                 memset(&p[2], 0, len - 2);
+                 return;
+        }
+}