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ipv6: format

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giomba 2021-12-24 17:56:17 +01:00
parent dc03eeb307
commit 3d206c0d23
2 changed files with 272 additions and 224 deletions
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406
src/ipv6.cpp
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@ -1,158 +1,190 @@
#include "ipv6.h" #include "ipv6.h"
#include "udp.h" #include "udp.h"
namespace ipv6 { namespace ipv6
/******** costants ********/ {
const IPv6Addr ALL_NODES_ADDRESS("\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"); /* ff02::1 */ /******** costants ********/
const IPv6Addr ALL_NODES_ADDRESS("\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"); /* ff02::1 */
/******** variables ********/ /******** variables ********/
uint8_t HOP_LIMIT = 64; uint8_t HOP_LIMIT = 64;
IPv6Addr LINK_LOCAL_ADDRESS; IPv6Addr LINK_LOCAL_ADDRESS;
IPv6Addr GLOBAL_ADDRESS; IPv6Addr GLOBAL_ADDRESS;
bool slaac_enable; bool slaac_enable;
/******** buffers ********/ /******** buffers ********/
IPv6Packet packetin; IPv6Packet packetin;
IPv6Packet packetout; IPv6Packet packetout;
/******** FUNCTIONS *******/ /******** FUNCTIONS *******/
void setEUI(const char* eui) { void setEUI(const char *eui)
memset(&LINK_LOCAL_ADDRESS, 0, 16); {
memcpy(&LINK_LOCAL_ADDRESS, "\xfe\x80", 2); memset(&LINK_LOCAL_ADDRESS, 0, 16);
memcpy( ((char*)&LINK_LOCAL_ADDRESS) + 8 , eui, 8); memcpy(&LINK_LOCAL_ADDRESS, "\xfe\x80", 2);
} memcpy(((char *)&LINK_LOCAL_ADDRESS) + 8, eui, 8);
void SLAAC(bool enable) {
slaac_enable = enable;
}
void setGlobalAddress(const char* address) {
memcpy(&GLOBAL_ADDRESS, address, 16);
}
uint16_t compute_checksum(const IPv6Addr* src_addr, const IPv6Addr* dst_addr, uint8_t next_header, int upper_len, const char* payload, int len) {
char buffer[LEN];
uint32_t total;
uint16_t* ptr;
int words;
int i = len;
/* prepare buffer with all data to checksum:
- the actual payload
- the pseudo ipv6 header
*/
/* actual payload */
memcpy(buffer, payload, len);
if (len % 2) { /* pad with 0 if length is odd */
buffer[len] = 0;
i++;
} }
/* pseudo ipv6 header -- see RFC 2460, Section 8.1 */ void SLAAC(bool enable)
memcpy(buffer + i, src_addr, 16); i += 16; {
memcpy(buffer + i, dst_addr, 16); i += 16; slaac_enable = enable;
memset(buffer + i, 0, 3); i+= 3; /* first 3 bytes always 0, because len always < 256 */ }
buffer[i] = upper_len & 0xff; i += 1; void setGlobalAddress(const char *address)
memset(buffer + i, 0, 3); i += 3; /* zero, as per-standard */ {
buffer[i] = next_header; i += 1; memcpy(&GLOBAL_ADDRESS, address, 16);
/* do computation */
total = 0;
ptr = (uint16_t*)buffer;
words = (i + 1) / 2;
while (words--) total += *ptr++;
while (total & 0xffff0000) {
total = (total >> 16) + (total & 0xffff);
} }
return ~((uint16_t) total); uint16_t compute_checksum(const IPv6Addr *src_addr, const IPv6Addr *dst_addr, uint8_t next_header, int upper_len, const char *payload, int len)
} {
char buffer[LEN];
uint32_t total;
uint16_t *ptr;
int words;
int i = len;
/******** IPv6Addr ********/ /* prepare buffer with all data to checksum:
IPv6Addr::IPv6Addr() {;} - the actual payload
- the pseudo ipv6 header
*/
/* actual payload */
memcpy(buffer, payload, len);
if (len % 2)
{ /* pad with 0 if length is odd */
buffer[len] = 0;
i++;
}
/* pseudo ipv6 header -- see RFC 2460, Section 8.1 */
memcpy(buffer + i, src_addr, 16);
i += 16;
memcpy(buffer + i, dst_addr, 16);
i += 16;
memset(buffer + i, 0, 3);
i += 3; /* first 3 bytes always 0, because len always < 256 */
buffer[i] = upper_len & 0xff;
i += 1;
memset(buffer + i, 0, 3);
i += 3; /* zero, as per-standard */
buffer[i] = next_header;
i += 1;
IPv6Addr::IPv6Addr(const char* address) { /* do computation */
memcpy(this->address, address, 16); total = 0;
} ptr = (uint16_t *)buffer;
words = (i + 1) / 2;
/******** IPv6Packet ********/ while (words--)
IPv6Packet::IPv6Packet() { total += *ptr++;
memset(packet, 0, LEN);
*(packet) = 0x60; /* IP version 6 */
*(packet + 7) = HOP_LIMIT; /* hop limit / ttl */
}
IPv6Packet::IPv6Packet(const char* buffer, int len) { while (total & 0xffff0000)
memcpy(this->packet, buffer, len); {
} total = (total >> 16) + (total & 0xffff);
}
void IPv6Packet::setNextHeader(uint8_t next_header) { return ~((uint16_t)total);
*(packet + 6) = next_header; }
}
void IPv6Packet::setLen(int len) { /******** IPv6Addr ********/
*(packet + 4) = len >> 8; IPv6Addr::IPv6Addr() { ; }
*(packet + 5) = len & 0xff;
}
int IPv6Packet::getLen() {
return ((*(packet + 4)) << 8) + (*(packet + 5));
}
void IPv6Packet::setSrcAddress(const IPv6Addr* address) { IPv6Addr::IPv6Addr(const char *address)
memcpy(packet + 8, address, 16); {
} memcpy(this->address, address, 16);
void IPv6Packet::setDstAddress(const IPv6Addr* address) { }
memcpy(packet + 24, address, 16);
}
const IPv6Addr* IPv6Packet::getSrcAddress() { /******** IPv6Packet ********/
return (const IPv6Addr*) (packet + 8); IPv6Packet::IPv6Packet()
} {
const IPv6Addr* IPv6Packet::getDstAddress() { memset(packet, 0, LEN);
return (const IPv6Addr*) (packet + 24); *(packet) = 0x60; /* IP version 6 */
} *(packet + 7) = HOP_LIMIT; /* hop limit / ttl */
}
void IPv6Packet::setFlow(const char* flow) { IPv6Packet::IPv6Packet(const char *buffer, int len)
/* three bytes {
4 most significant bits are ignored memcpy(this->packet, buffer, len);
because only 20 bits can be used */ }
*(packet + 1) = (*(packet + 1)) | (flow[0] & 0x0f); /* pay attention to TC field */
memcpy(packet + 2, flow + 1, 2);
}
void IPv6Packet::setPayload(char* payload, int len) { void IPv6Packet::setNextHeader(uint8_t next_header)
*(packet + 4 + 0) = len >> 8; {
*(packet + 4 + 1) = len & 0xff; *(packet + 6) = next_header;
memcpy(packet + 40, payload, len); /* payload */ }
}
void IPv6Packet::send() { void IPv6Packet::setLen(int len)
slip::send(packet, 40 + this->getLen()); {
} *(packet + 4) = len >> 8;
*(packet + 5) = len & 0xff;
}
int IPv6Packet::getLen()
{
return ((*(packet + 4)) << 8) + (*(packet + 5));
}
void IPv6Packet::doAction() { void IPv6Packet::setSrcAddress(const IPv6Addr *address)
/* if destination is my address (global or link-local), or destination is "all nodes" address, then... */ {
if ( memcpy(packet + 8, address, 16);
(memcmp(&(ALL_NODES_ADDRESS), packet + 24, 16) == 0) || }
(memcmp(&(LINK_LOCAL_ADDRESS), packet + 24, 16) == 0) || void IPv6Packet::setDstAddress(const IPv6Addr *address)
(memcmp(&(GLOBAL_ADDRESS), packet + 24, 16) == 0)) { {
int ilen = this->getLen(); /* input payload length */ memcpy(packet + 24, address, 16);
int olen; /* output payload length */ }
switch(*(packet + 6)) { /* next header */ const IPv6Addr *IPv6Packet::getSrcAddress()
{
return (const IPv6Addr *)(packet + 8);
}
const IPv6Addr *IPv6Packet::getDstAddress()
{
return (const IPv6Addr *)(packet + 24);
}
void IPv6Packet::setFlow(const char *flow)
{
/* three bytes
4 most significant bits are ignored
because only 20 bits can be used */
*(packet + 1) = (*(packet + 1)) | (flow[0] & 0x0f); /* pay attention to TC field */
memcpy(packet + 2, flow + 1, 2);
}
void IPv6Packet::setPayload(char *payload, int len)
{
*(packet + 4 + 0) = len >> 8;
*(packet + 4 + 1) = len & 0xff;
memcpy(packet + 40, payload, len); /* payload */
}
void IPv6Packet::send()
{
slip::send(packet, 40 + this->getLen());
}
void IPv6Packet::doAction()
{
/* if destination is my address (global or link-local), or destination is "all nodes" address, then... */
if (
(memcmp(&(ALL_NODES_ADDRESS), packet + 24, 16) == 0) ||
(memcmp(&(LINK_LOCAL_ADDRESS), packet + 24, 16) == 0) ||
(memcmp(&(GLOBAL_ADDRESS), packet + 24, 16) == 0))
{
int ilen = this->getLen(); /* input payload length */
int olen; /* output payload length */
switch (*(packet + 6))
{ /* next header */
case NH_ICMP: case NH_ICMP:
if ((olen = handleICMP((char*)&packetout + 40, packet + 40, ilen)) != -1) { if ((olen = handleICMP((char *)&packetout + 40, packet + 40, ilen)) != -1)
{
packetout.setLen(olen); packetout.setLen(olen);
packetout.setFlow(((char*)(&packetin)) + 1); packetout.setFlow(((char *)(&packetin)) + 1);
packetout.setSrcAddress(packetin.getDstAddress()); packetout.setSrcAddress(packetin.getDstAddress());
packetout.setDstAddress(packetin.getSrcAddress()); packetout.setDstAddress(packetin.getSrcAddress());
packetout.setNextHeader(NH_ICMP); packetout.setNextHeader(NH_ICMP);
packetout.send(); packetout.send();
} }
break; break;
case NH_UDP: case NH_UDP:
if ((olen = udp::handleUDP((char*)&packetout + 40, packet + 40, ilen)) != -1) { if ((olen = udp::handleUDP((char *)&packetout + 40, packet + 40, ilen)) != -1)
{
packetout.setLen(olen); packetout.setLen(olen);
packetout.setFlow(((char*)(&packetin)) + 1); packetout.setFlow(((char *)(&packetin)) + 1);
packetout.setSrcAddress(packetin.getDstAddress()); packetout.setSrcAddress(packetin.getDstAddress());
packetout.setDstAddress(packetin.getSrcAddress()); packetout.setDstAddress(packetin.getSrcAddress());
packetout.setNextHeader(NH_UDP); packetout.setNextHeader(NH_UDP);
@ -162,72 +194,80 @@ void IPv6Packet::doAction() {
default: default:
/* no other protocols are known here, sorry :-) */ /* no other protocols are known here, sorry :-) */
break; break;
} }
} /* ...else discard packet */ } /* ...else discard packet */
}
/* handles ICMP and (possibly) generate a reply
* returns length of generated packet (written to output_buffer), or -1 if there is no reply packet
*/
int handleICMP(char* output_buffer, const char* input_buffer, int len) {
uint8_t type = *(input_buffer);
/* compute checksum, and assert validity of incoming message */
char received_checksum[2];
memcpy(received_checksum, input_buffer + 2, 2);
memcpy(output_buffer, input_buffer, len);
memset(output_buffer + 2, 0, 2); /* zero-checksum */
uint16_t computed_checksum = compute_checksum(
packetin.getSrcAddress(),
packetin.getDstAddress(),
NH_ICMP,
len,
output_buffer,
len);
if (memcmp(&computed_checksum, received_checksum, 2) != 0) { /* if checksum is not valid, return */
return -1;
} }
if (type == ICMP_ECHO_REQUEST_TYPE) { /* if it is ICMPv6 Echo Request, then... */ /* handles ICMP and (possibly) generate a reply
/* Build an echo reply: * returns length of generated packet (written to output_buffer), or -1 if there is no reply packet
* the reply has the same exact format of the request, */
* except for Type and Checksum */ int handleICMP(char *output_buffer, const char *input_buffer, int len)
*(output_buffer) = ICMP_ECHO_REPLY_TYPE; {
memset(output_buffer + 2, 0, 2); /* zero-checksum */ uint8_t type = *(input_buffer);
uint16_t checksum = compute_checksum( /* compute checksum, and assert validity of incoming message */
packetin.getDstAddress(), char received_checksum[2];
packetin.getSrcAddress(), memcpy(received_checksum, input_buffer + 2, 2);
NH_ICMP,
len, memcpy(output_buffer, input_buffer, len);
output_buffer, memset(output_buffer + 2, 0, 2); /* zero-checksum */
len); uint16_t computed_checksum = compute_checksum(
memcpy(output_buffer + 2, &checksum, 2); packetin.getSrcAddress(),
return len; packetin.getDstAddress(),
NH_ICMP,
} else if (type == ICMP_RADV_TYPE && slaac_enable) { /* if it is IVMPc6 Router Advertisement, then... */ len,
ICMPv6_RADV* radv = (ICMPv6_RADV*)input_buffer; output_buffer,
HOP_LIMIT = (radv->cur_hop_limit != 0) ? radv->cur_hop_limit : 64; len);
for ( if (memcmp(&computed_checksum, received_checksum, 2) != 0)
ICMPv6_RADV_Option* option = (ICMPv6_RADV_Option*) (radv + 1); { /* if checksum is not valid, return */
option != input_buffer + len; return -1;
option = (ICMPv6_RADV_Option*) ( ((char*)(option)) + option->len )) { }
if (option->type == 3 && option->len == 4) { /* if it is a ICMPv6 Prefix Information, then... */
ICMPv6_RADV_PrefixInformation* p = (ICMPv6_RADV_PrefixInformation*) option; if (type == ICMP_ECHO_REQUEST_TYPE)
{ /* if it is ICMPv6 Echo Request, then... */
if (p->prefix_length != 64) continue; /* only /64 prefix is supported */ /* Build an echo reply:
if (! (p->la_flags & 0x40)) continue; /* only SLAAC is supported */ * the reply has the same exact format of the request,
* except for Type and Checksum */
*(output_buffer) = ICMP_ECHO_REPLY_TYPE;
memset(output_buffer + 2, 0, 2); /* zero-checksum */
uint16_t checksum = compute_checksum(
packetin.getDstAddress(),
packetin.getSrcAddress(),
NH_ICMP,
len,
output_buffer,
len);
memcpy(output_buffer + 2, &checksum, 2);
return len;
}
else if (type == ICMP_RADV_TYPE && slaac_enable)
{ /* if it is IVMPc6 Router Advertisement, then... */
ICMPv6_RADV *radv = (ICMPv6_RADV *)input_buffer;
HOP_LIMIT = (radv->cur_hop_limit != 0) ? radv->cur_hop_limit : 64;
for (
ICMPv6_RADV_Option *option = (ICMPv6_RADV_Option *)(radv + 1);
option != input_buffer + len;
option = (ICMPv6_RADV_Option *)(((char *)(option)) + option->len))
{
if (option->type == 3 && option->len == 4)
{ /* if it is a ICMPv6 Prefix Information, then... */
ICMPv6_RADV_PrefixInformation *p = (ICMPv6_RADV_PrefixInformation *)option;
if (p->prefix_length != 64)
continue; /* only /64 prefix is supported */
if (!(p->la_flags & 0x40))
continue; /* only SLAAC is supported */
memcpy(&GLOBAL_ADDRESS, p->prefix, 8); /* set prefix -- leave host bits unchanged */ memcpy(&GLOBAL_ADDRESS, p->prefix, 8); /* set prefix -- leave host bits unchanged */
break; break;
} }
}
return -1;
} }
return -1; return -1;
} }
return -1;
}
} }

90
src/ipv6.h
View File

@ -4,47 +4,52 @@
#include "Arduino.h" #include "Arduino.h"
#include "slip.h" #include "slip.h"
namespace ipv6 { namespace ipv6
{
/* maximum length for an IPv6 packet */ /* maximum length for an IPv6 packet */
const uint8_t LEN = 128; const uint8_t LEN = 128;
/* ICMP Types */ /* ICMP Types */
const uint8_t ICMP_ECHO_REQUEST_TYPE = 128; const uint8_t ICMP_ECHO_REQUEST_TYPE = 128;
const uint8_t ICMP_ECHO_REPLY_TYPE = 129; const uint8_t ICMP_ECHO_REPLY_TYPE = 129;
const uint8_t ICMP_RADV_TYPE = 134; const uint8_t ICMP_RADV_TYPE = 134;
/* Next-Header Types */ /* Next-Header Types */
const uint8_t NH_ICMP = 58; const uint8_t NH_ICMP = 58;
const uint8_t NH_UDP = 17; const uint8_t NH_UDP = 17;
class IPv6Addr { class IPv6Addr
private: {
char address[16]; private:
public: char address[16];
IPv6Addr();
IPv6Addr(const char* address); public:
IPv6Addr();
IPv6Addr(const char *address);
}; };
extern const IPv6Addr ALL_NODES_ADDRESS; extern const IPv6Addr ALL_NODES_ADDRESS;
class IPv6Packet { class IPv6Packet
private: {
char packet[LEN]; private:
public: char packet[LEN];
IPv6Packet();
IPv6Packet(const char* buffer, int len);
void setLen(int len);
int getLen();
void setSrcAddress(const IPv6Addr* address);
const IPv6Addr* getSrcAddress();
void setDstAddress(const IPv6Addr* address);
const IPv6Addr* getDstAddress();
void setNextHeader(uint8_t next_header);
void setFlow(const char* flow);
void setPayload(char* payload, int len);
void send();
void doAction(); public:
IPv6Packet();
IPv6Packet(const char *buffer, int len);
void setLen(int len);
int getLen();
void setSrcAddress(const IPv6Addr *address);
const IPv6Addr *getSrcAddress();
void setDstAddress(const IPv6Addr *address);
const IPv6Addr *getDstAddress();
void setNextHeader(uint8_t next_header);
void setFlow(const char *flow);
void setPayload(char *payload, int len);
void send();
void doAction();
}; };
/* incoming and outgoing packets buffer */ /* incoming and outgoing packets buffer */
@ -52,20 +57,21 @@ namespace ipv6 {
extern IPv6Packet packetout; extern IPv6Packet packetout;
/* Note: content of message may be changed */ /* Note: content of message may be changed */
int handleICMP(char* output_buffer, const char* input_buffer, int len); int handleICMP(char *output_buffer, const char *input_buffer, int len);
/* Compute internet checksum. Actually it is not so straightforward: */ /* Compute internet checksum. Actually it is not so straightforward: */
uint16_t compute_checksum( uint16_t compute_checksum(
const IPv6Addr* src_addr, /* source IPv6 address */ const IPv6Addr *src_addr, /* source IPv6 address */
const IPv6Addr* dst_addr, /* destination IPv6 address */ const IPv6Addr *dst_addr, /* destination IPv6 address */
uint8_t next_header, /* IPv6 next header number */ uint8_t next_header, /* IPv6 next header number */
int upper_len, /* length as found in the upper layer protocol */ int upper_len, /* length as found in the upper layer protocol */
const char* payload, /* IPv6 payload */ const char *payload, /* IPv6 payload */
int len /* IPv6 payload length */ int len /* IPv6 payload length */
); );
/* RFC 4861 -- begin */ /* RFC 4861 -- begin */
struct ICMPv6_RADV { struct ICMPv6_RADV
{
uint8_t type; uint8_t type;
uint8_t code; uint8_t code;
char checksum[2]; char checksum[2];
@ -76,12 +82,14 @@ namespace ipv6 {
uint32_t retrans_time; uint32_t retrans_time;
}; };
struct ICMPv6_RADV_Option { struct ICMPv6_RADV_Option
{
uint8_t type; uint8_t type;
uint8_t len; uint8_t len;
}; };
struct ICMPv6_RADV_PrefixInformation { struct ICMPv6_RADV_PrefixInformation
{
uint8_t type; uint8_t type;
uint8_t len; uint8_t len;
uint8_t prefix_length; uint8_t prefix_length;
@ -93,9 +101,9 @@ namespace ipv6 {
}; };
/* RFC 4861 -- end */ /* RFC 4861 -- end */
void setEUI(const char* eui); /* 64bit Extended Unique Identifier */ void setEUI(const char *eui); /* 64bit Extended Unique Identifier */
void SLAAC(bool enable); /* enable IPv6 automatic prefix configuration (listens for RADV) */ void SLAAC(bool enable); /* enable IPv6 automatic prefix configuration (listens for RADV) */
void setGlobalAddress(const char* address); /* global IPv6 address, manually configured */ void setGlobalAddress(const char *address); /* global IPv6 address, manually configured */
} }
#endif #endif