[src/trunk]: src/sys/netipsec Rename padding -> padlen, pad -> tail, and clar...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8f9aefe003ae
branches:  trunk
changeset: 323073:8f9aefe003ae
user:      maxv <maxv%NetBSD.org@localhost>
date:      Wed May 30 16:15:19 2018 +0000

description:
Rename padding -> padlen, pad -> tail, and clarify.

diffstat:

 sys/netipsec/xform_esp.c |  51 ++++++++++++++++++++++++-----------------------
 1 files changed, 26 insertions(+), 25 deletions(-)

diffs (134 lines):

diff -r d8acc62e415e -r 8f9aefe003ae sys/netipsec/xform_esp.c
--- a/sys/netipsec/xform_esp.c  Wed May 30 13:20:39 2018 +0000
+++ b/sys/netipsec/xform_esp.c  Wed May 30 16:15:19 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: xform_esp.c,v 1.89 2018/05/18 19:02:49 maxv Exp $      */
+/*     $NetBSD: xform_esp.c,v 1.90 2018/05/30 16:15:19 maxv Exp $      */
 /*     $FreeBSD: xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $   */
 /*     $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
 
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.89 2018/05/18 19:02:49 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.90 2018/05/30 16:15:19 maxv Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_inet.h"
@@ -687,11 +687,11 @@
        char buf[IPSEC_ADDRSTRLEN];
        const struct enc_xform *espx;
        const struct auth_hash *esph;
-       int hlen, rlen, padding, blks, alen, i, roff;
+       int hlen, rlen, padlen, blks, alen, i, roff;
        struct mbuf *mo = NULL;
        struct tdb_crypto *tc;
        struct secasindex *saidx;
-       unsigned char *pad;
+       unsigned char *tail;
        uint8_t prot;
        int error, maxpacketsize;
 
@@ -699,28 +699,30 @@
        struct cryptop *crp;
 
        esph = sav->tdb_authalgxform;
-       KASSERT(sav->tdb_encalgxform != NULL);
        espx = sav->tdb_encalgxform;
+       KASSERT(espx != NULL);
 
        if (sav->flags & SADB_X_EXT_OLD)
                hlen = sizeof(struct esp) + sav->ivlen;
        else
                hlen = sizeof(struct newesp) + sav->ivlen;
 
-       rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
+       if (esph)
+               alen = esph->authsize;
+       else
+               alen = 0;
+
        /*
         * NB: The null encoding transform has a blocksize of 4
         *     so that headers are properly aligned.
         */
        blks = espx->blocksize;         /* IV blocksize */
 
-       /* XXX clamp padding length a la KAME??? */
-       padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
+       /* Raw payload length. */
+       rlen = m->m_pkthdr.len - skip;
 
-       if (esph)
-               alen = esph->authsize;
-       else
-               alen = 0;
+       /* XXX clamp padding length a la KAME??? */
+       padlen = ((blks - ((rlen + 2) % blks)) % blks) + 2;
 
        ESP_STATINC(ESP_STAT_OUTPUT);
 
@@ -746,12 +748,12 @@
                error = EPFNOSUPPORT;
                goto bad;
        }
-       if (skip + hlen + rlen + padding + alen > maxpacketsize) {
+       if (skip + hlen + rlen + padlen + alen > maxpacketsize) {
                DPRINTF(("%s: packet in SA %s/%08lx got too big (len %u, "
                    "max len %u)\n", __func__,
                    ipsec_address(&saidx->dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi),
-                   skip + hlen + rlen + padding + alen, maxpacketsize));
+                   skip + hlen + rlen + padlen + alen, maxpacketsize));
                ESP_STATINC(ESP_STAT_TOOBIG);
                error = EMSGSIZE;
                goto bad;
@@ -799,15 +801,14 @@
        }
 
        /*
-        * Add padding -- better to do it ourselves than use the crypto engine,
-        * although if/when we support compression, we'd have to do that.
+        * Grow the mbuf, we will append data at the tail.
         */
-       pad = m_pad(m, padding + alen);
-       if (pad == NULL) {
+       tail = m_pad(m, padlen + alen);
+       if (tail == NULL) {
                DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
                    ipsec_address(&saidx->dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi)));
-               m = NULL;               /* NB: free'd by m_pad */
+               m = NULL;
                error = ENOBUFS;
                goto bad;
        }
@@ -817,21 +818,21 @@
         */
        switch (sav->flags & SADB_X_EXT_PMASK) {
        case SADB_X_EXT_PSEQ:
-               for (i = 0; i < padding - 2; i++)
-                       pad[i] = i+1;
+               for (i = 0; i < padlen - 2; i++)
+                       tail[i] = i + 1;
                break;
        case SADB_X_EXT_PRAND:
-               (void)cprng_fast(pad, padding - 2);
+               (void)cprng_fast(tail, padlen - 2);
                break;
        case SADB_X_EXT_PZERO:
        default:
-               memset(pad, 0, padding - 2);
+               memset(tail, 0, padlen - 2);
                break;
        }
 
        /* Fix padding length and Next Protocol in padding itself. */
-       pad[padding - 2] = padding - 2;
-       m_copydata(m, protoff, sizeof(uint8_t), pad + padding - 1);
+       tail[padlen - 2] = padlen - 2;
+       m_copydata(m, protoff, sizeof(uint8_t), tail + padlen - 1);
 
        /* Fix Next Protocol in IPv4/IPv6 header. */
        prot = IPPROTO_ESP;