From: Tom Gundersen <teg@jklm.no>
Date: Sat, 1 Nov 2014 13:32:28 +0000 (+0100)
Subject: dhcp6: use unaligned read/write helpers
X-Git-Tag: v218~622
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=4903a73c37d444261c0a6b362e1c27e58100ea72

dhcp6: use unaligned read/write helpers
---

diff --git a/src/libsystemd-network/dhcp6-option.c b/src/libsystemd-network/dhcp6-option.c
index e6a31778f..a46b6e309 100644
--- a/src/libsystemd-network/dhcp6-option.c
+++ b/src/libsystemd-network/dhcp6-option.c
@@ -24,31 +24,37 @@
 #include <string.h>
 
 #include "sparse-endian.h"
+#include "unaligned.h"
 #include "util.h"
 
 #include "dhcp6-internal.h"
 #include "dhcp6-protocol.h"
 
-#define DHCP6_OPTION_HDR_LEN                    4
 #define DHCP6_OPTION_IA_NA_LEN                  12
 #define DHCP6_OPTION_IA_TA_LEN                  4
 
+typedef struct DHCP6Option {
+        be16_t code;
+        be16_t len;
+        uint8_t data[];
+} DHCP6Option;
+
 static int option_append_hdr(uint8_t **buf, size_t *buflen, uint16_t optcode,
                              size_t optlen) {
+        DHCP6Option *option = (DHCP6Option*) *buf; /* unaligned! */
+
         assert_return(buf, -EINVAL);
         assert_return(*buf, -EINVAL);
         assert_return(buflen, -EINVAL);
 
-        if (optlen > 0xffff || *buflen < optlen + DHCP6_OPTION_HDR_LEN)
+        if (optlen > 0xffff || *buflen < optlen + sizeof(DHCP6Option))
                 return -ENOBUFS;
 
-        (*buf)[0] = optcode >> 8;
-        (*buf)[1] = optcode & 0xff;
-        (*buf)[2] = optlen >> 8;
-        (*buf)[3] = optlen & 0xff;
+        unaligned_write_be16(&option->code, optcode);
+        unaligned_write_be16(&option->len, (uint16_t) optlen);
 
-        *buf += DHCP6_OPTION_HDR_LEN;
-        *buflen -= DHCP6_OPTION_HDR_LEN;
+        *buf += sizeof(DHCP6Option);
+        *buflen -= sizeof(DHCP6Option);
 
         return 0;
 }
@@ -100,8 +106,8 @@ int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
         ia_hdr = *buf;
         ia_buflen = *buflen;
 
-        *buf += DHCP6_OPTION_HDR_LEN;
-        *buflen -= DHCP6_OPTION_HDR_LEN;
+        *buf += sizeof(DHCP6Option);
+        *buflen -= sizeof(DHCP6Option);
 
         memcpy(*buf, &ia->id, len);
 
@@ -119,7 +125,7 @@ int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
                 *buf += sizeof(addr->iaaddr);
                 *buflen -= sizeof(addr->iaaddr);
 
-                ia_addrlen += DHCP6_OPTION_HDR_LEN + sizeof(addr->iaaddr);
+                ia_addrlen += sizeof(DHCP6Option) + sizeof(addr->iaaddr);
         }
 
         r = option_append_hdr(&ia_hdr, &ia_buflen, ia->type, len + ia_addrlen);
@@ -130,23 +136,24 @@ int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
 }
 
 
-static int option_parse_hdr(uint8_t **buf, size_t *buflen, uint16_t *opt,
+static int option_parse_hdr(uint8_t **buf, size_t *buflen, uint16_t *optcode,
                             size_t *optlen) {
+        DHCP6Option *option = (DHCP6Option*) *buf; /* unaligned! */
         uint16_t len;
 
         assert_return(buf, -EINVAL);
-        assert_return(opt, -EINVAL);
+        assert_return(optcode, -EINVAL);
         assert_return(optlen, -EINVAL);
 
-        if (*buflen < 4)
+        if (*buflen < sizeof(DHCP6Option))
                 return -ENOMSG;
 
-        len = (*buf)[2] << 8 | (*buf)[3];
+        len = unaligned_read_be16(&option->len);
 
         if (len > *buflen)
                 return -ENOMSG;
 
-        *opt = (*buf)[0] << 8 | (*buf)[1];
+        *optcode = unaligned_read_be16(&option->code);
         *optlen = len;
 
         *buf += 4;
@@ -190,7 +197,7 @@ int dhcp6_option_parse_ia(uint8_t **buf, size_t *buflen, uint16_t iatype,
         switch (iatype) {
         case DHCP6_OPTION_IA_NA:
 
-                if (*buflen < DHCP6_OPTION_IA_NA_LEN + DHCP6_OPTION_HDR_LEN +
+                if (*buflen < DHCP6_OPTION_IA_NA_LEN + sizeof(DHCP6Option) +
                     sizeof(addr->iaaddr)) {
                         r = -ENOBUFS;
                         goto error;
@@ -212,7 +219,7 @@ int dhcp6_option_parse_ia(uint8_t **buf, size_t *buflen, uint16_t iatype,
                 break;
 
         case DHCP6_OPTION_IA_TA:
-                if (*buflen < DHCP6_OPTION_IA_TA_LEN + DHCP6_OPTION_HDR_LEN +
+                if (*buflen < DHCP6_OPTION_IA_TA_LEN + sizeof(DHCP6Option) +
                     sizeof(addr->iaaddr)) {
                         r = -ENOBUFS;
                         goto error;