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fib: changed handling of the net prefix
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Until now the prefix length has been determined automatically by the FIB
This PR changes it to be provided as msb(yte) in the global_flags of an entry
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BytesGalore authored and BytesGalore committed Mar 30, 2016
1 parent 18b7c8e commit 1bc9c3b
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Showing 7 changed files with 146 additions and 82 deletions.
9 changes: 7 additions & 2 deletions sys/include/net/fib.h
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Original file line number Diff line number Diff line change
Expand Up @@ -78,9 +78,14 @@ typedef struct fib_destination_set_entry_t {
#define FIB_FLAG_RPL_ROUTE (1UL << 0)

/**
* @brief flag to identify if the FIB-Entry is a net prefix (MSB == 1)
* @brief flag used as shift for the net prefix length in bits
*/
#define FIB_FLAG_NET_PREFIX (1UL<<31)
#define FIB_FLAG_NET_PREFIX_SHIFT (24)

/**
* @brief flag used as mask for the net prefix length in bits
*/
#define FIB_FLAG_NET_PREFIX_MASK (0xffUL << FIB_FLAG_NET_PREFIX_SHIFT)

/**
* @brief initializes all FIB entries with 0
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13 changes: 2 additions & 11 deletions sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c
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Original file line number Diff line number Diff line change
Expand Up @@ -451,7 +451,7 @@ bool _parse_options(int msg_type, gnrc_rpl_instance_t *inst, gnrc_rpl_opt_t *opt
uint32_t fib_dst_flags = 0;

if (target->prefix_length < IPV6_ADDR_BIT_LEN) {
fib_dst_flags |= FIB_FLAG_NET_PREFIX;
fib_dst_flags = ((uint32_t)(target->prefix_length) << FIB_FLAG_NET_PREFIX_SHIFT);
}

DEBUG("RPL: adding fib entry %s/%d 0x%x\n",
Expand Down Expand Up @@ -816,16 +816,7 @@ void gnrc_rpl_send_DAO(gnrc_rpl_instance_t *inst, ipv6_addr_t *destination, uint
}
addr = (ipv6_addr_t *) fentry->global->address;
if (ipv6_addr_is_global(addr)) {
size_t prefix_length;

if (fentry->global_flags & FIB_FLAG_NET_PREFIX) {
universal_address_compare(fentry->global,
fentry->global->address,
&prefix_length);
}
else {
prefix_length = IPV6_ADDR_BIT_LEN;
}
size_t prefix_length = (fentry->global_flags >> FIB_FLAG_NET_PREFIX_SHIFT);

DEBUG("RPL: Send DAO - building target %s/%d\n",
ipv6_addr_to_str(addr_str, addr, sizeof(addr_str)),
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6 changes: 3 additions & 3 deletions sys/net/gnrc/routing/rpl/gnrc_rpl_dodag.c
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Original file line number Diff line number Diff line change
Expand Up @@ -204,7 +204,7 @@ bool gnrc_rpl_parent_remove(gnrc_rpl_parent_t *parent)
dodag->iface,
(uint8_t *) ipv6_addr_unspecified.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_NET_PREFIX,
0x0,
parent->next->addr.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_RPL_ROUTE,
Expand Down Expand Up @@ -248,7 +248,7 @@ void gnrc_rpl_parent_update(gnrc_rpl_dodag_t *dodag, gnrc_rpl_parent_t *parent)
dodag->iface,
(uint8_t *) ipv6_addr_unspecified.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_NET_PREFIX,
0x00,
parent->addr.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_RPL_ROUTE,
Expand Down Expand Up @@ -300,7 +300,7 @@ static gnrc_rpl_parent_t *_gnrc_rpl_find_preferred_parent(gnrc_rpl_dodag_t *doda
dodag->iface,
(uint8_t *) ipv6_addr_unspecified.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_NET_PREFIX,
0x00,
dodag->parents->addr.u8,
sizeof(ipv6_addr_t),
FIB_FLAG_RPL_ROUTE,
Expand Down
40 changes: 29 additions & 11 deletions sys/net/network_layer/fib/fib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -132,23 +132,39 @@ static int fib_find_entry(fib_table_t *table, uint8_t *dst, size_t dst_size,

int ret_comp = universal_address_compare(table->data.entries[i].global, dst, &match_size);
/* If we found an exact match */
if (ret_comp == 0 || (is_all_zeros_addr && match_size == 0)) {
DEBUG("[fib_find_entry] found an exact match");
if ((ret_comp == 0) || (is_all_zeros_addr && (match_size == 0) && (ret_comp == 2))) {
entry_arr[0] = &(table->data.entries[i]);
*entry_arr_size = 1;
/* we will not find a better one so we return */
return 1;
}
else {
/* we try to find the most fitting prefix */
if ((ret_comp == 1)
&& (table->data.entries[i].global_flags & FIB_FLAG_NET_PREFIX)) {
if ((prefix_size == 0) || (match_size > prefix_size)) {
if (ret_comp == 1) {
if (table->data.entries[i].global_flags & FIB_FLAG_NET_PREFIX_MASK) {
/* we shift the most upper flag byte back to get the number of prefix bits */
size_t global_prefix_len = (table->data.entries[i].global_flags
& FIB_FLAG_NET_PREFIX_MASK) >> FIB_FLAG_NET_PREFIX_SHIFT;

if ((match_size >= global_prefix_len) &&
((prefix_size == 0) || (match_size > prefix_size))) {
entry_arr[0] = &(table->data.entries[i]);
/* we could find a better one so we move on */
ret = 0;

prefix_size = match_size;
count = 1;
}
}
}
else if (ret_comp == 2) {
/* we found the default gateway entry, e.g. ::/0 for IPv6
* and we keep it only if there is no better one
*/
if (prefix_size == 0) {
entry_arr[0] = &(table->data.entries[i]);
/* we could find a better one so we move on */
ret = 0;

prefix_size = match_size;
count = 1;
}
}
Expand Down Expand Up @@ -1516,17 +1532,19 @@ void fib_print_routes(fib_table_t *table)
uint64_t now = xtimer_now64();

if (table->table_type == FIB_TABLE_TYPE_SH) {
printf("%-" FIB_ADDR_PRINT_LENS "s %-10s %-" FIB_ADDR_PRINT_LENS "s %-10s %-16s"
printf("%-" FIB_ADDR_PRINT_LENS "s %-17s %-" FIB_ADDR_PRINT_LENS "s %-10s %-16s"
" Interface\n" , "Destination", "Flags", "Next Hop", "Flags", "Expires");

for (size_t i = 0; i < table->size; ++i) {
if (table->data.entries[i].lifetime != 0) {
fib_print_address(table->data.entries[i].global);
printf(" 0x%08"PRIx32" ", table->data.entries[i].global_flags);
if(table->data.entries[i].global_flags & FIB_FLAG_NET_PREFIX) {
printf("N ");
if(table->data.entries[i].global_flags & FIB_FLAG_NET_PREFIX_MASK) {
uint32_t prefix = (table->data.entries[i].global_flags
& FIB_FLAG_NET_PREFIX_MASK);
printf("N /%-3d ", (int)(prefix >> FIB_FLAG_NET_PREFIX_SHIFT));
} else {
printf("H ");
printf("H ");
}

fib_print_address(table->data.entries[i].next_hop);
Expand Down
37 changes: 23 additions & 14 deletions sys/shell/commands/sc_fib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@

#define INFO1_TXT "fibroute add <destination> via <next hop> [dev <device>]"
#define INFO2_TXT " [lifetime <lifetime>]"
#define INFO3_TXT " <destination> - the destination address\n" \
#define INFO3_TXT " <destination> - the destination address with optional prefix size, e.g. /116\n" \
" <next hop> - the address of the next-hop towards the <destination>\n" \
" <device> - the device id of the Interface to use." \
" Optional if only one interface is available.\n"
Expand Down Expand Up @@ -79,15 +79,33 @@ static void _fib_usage(int info)

static void _fib_add(const char *dest, const char *next, kernel_pid_t pid, uint32_t lifetime)
{
unsigned char *dst = (unsigned char *)dest;
size_t dst_size = (strlen(dest));
uint32_t prefix = 0;
/* Get the prefix length */
size_t i = 0;
for (i = strlen(dest); i > 0; --i) {
if (dest[i] == '/') {
prefix = atoi(&dest[i+1]);
break;
}
if (dest[i] == ':' || dest[i] == '.') {
i = strlen(dest);
break;
}
}

size_t dst_size = (i+1);
unsigned char dst_arr[dst_size];
memset(dst_arr, 0, dst_size);
memcpy(dst_arr, dest, i);
unsigned char *dst = &dst_arr[0];
uint32_t dst_flags = 0;

unsigned char *nxt = (unsigned char *)next;
size_t nxt_size = (strlen(next));
uint32_t nxt_flags = 0;

/* determine destination address */
if (inet_pton(AF_INET6, dest, tmp_ipv6_dst)) {
if (inet_pton(AF_INET6, (char*)dst, tmp_ipv6_dst)) {
dst = tmp_ipv6_dst;
dst_size = IN6ADDRSZ;
}
Expand All @@ -106,16 +124,7 @@ static void _fib_add(const char *dest, const char *next, kernel_pid_t pid, uint3
nxt_size = INADDRSZ;
}

/* Set the prefix flag for a network */
dst_flags |= FIB_FLAG_NET_PREFIX;
for (size_t i = 0; i < dst_size; ++i) {
if (dst[i] != 0) {
/* and clear the bit if its not the default route */
dst_flags = (dst_flags & ~FIB_FLAG_NET_PREFIX);
break;
}
}

dst_flags |= (prefix << FIB_FLAG_NET_PREFIX_SHIFT);
fib_add_entry(&gnrc_ipv6_fib_table, pid, dst, dst_size, dst_flags, nxt,
nxt_size, nxt_flags, lifetime);
}
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62 changes: 34 additions & 28 deletions sys/universal_address/universal_address.c
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Original file line number Diff line number Diff line change
Expand Up @@ -196,41 +196,47 @@ int universal_address_compare(universal_address_container_t *entry,
return ret;
}

/* Get the index of the first trailing `0` (indicates a prefix) */
int i = 0;
for( i = entry->address_size-1; i > 0; --i) {
if( entry->address[i] != 0 ) {
/* compare up to fist distinct byte, pretty clumsy method for now */
int idx = -1;
bool test_all_zeros = true;
for (size_t i = 0; i < entry->address_size; i++) {
if ((idx == -1) && (entry->address[i] != addr[i])) {
idx = i;
}
if (test_all_zeros) {
test_all_zeros = (entry->address[i] == 0);
}
if ((idx != -1) && !test_all_zeros) {
break;
}
}

if( memcmp(entry->address, addr, i) == 0 ) {
/* if the bytes-1 equals we check the bits of the lowest byte */
uint8_t bitmask = 0x00;
uint8_t j = 0;
/* get a bitmask for the trailing 0b */
for( ; j < 8; ++j ) {
if ( (entry->address[i] >> j) & 0x01 ) {
bitmask = 0xff << j;
break;
}
}
if( (entry->address[i] & bitmask) == (addr[i] & bitmask) ) {
ret = entry->address[i] != addr[i];
*addr_size_in_bits = (i<<3) + (8-j);
if( ret == 0 ) {
/* check if the remaining bits from addr are significant */
i++;
for(; i < entry->address_size; ++i) {
if( addr[i] != 0 ) {
ret = 1;
break;
}
}
}
/* if the address is all 0 its a default route address */
if (test_all_zeros) {
*addr_size_in_bits = 0;
mutex_unlock(&mtx_access);
return 2;
}

/* if we have no distinct bytes the addresses are equal */
if (idx == -1) {
mutex_unlock(&mtx_access);
return 0;
}

/* count equal bits */
uint8_t xor = entry->address[idx]^addr[idx];
int8_t j = 7;
for ( ; j > 0; --j) {
if ((xor >> j) & 0x01) {
break;
}
}

/* get the total number of matching bits */
*addr_size_in_bits = (idx << 3) + j;
ret = 1;

mutex_unlock(&mtx_access);
return ret;
}
Expand Down
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