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proxy_ptc.c
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proxy_ptc.c
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#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "proxy_ptc.h"
#define GET_NEXT_WORD() \
word = pp_strtok(NULL, " ", &saveptr); \
if (!word) { \
return PPHDRERR; \
}
/* get_addr_family() : determine addr family and return
* I/P
* addr : sockaddr_storage address (IPv4/IPv6)
* O/P
* ret : AF_INET/AF_INET6, on error 0
*/
uint8_t get_addr_family(struct sockaddr_storage *addr) {
struct sockaddr_in *sin;
struct sockaddr_in6 *sin6;
sin = (struct sockaddr_in *)addr;
if(sin->sin_family == AF_INET) {
return AF_INET;
}
sin6 = (struct sockaddr_in6 *)addr;
if(sin6->sin6_family == AF_INET6) {
return AF_INET6;
}
return 0;
}
struct in_addr get_inet4_ip(struct sockaddr_storage *addr) {
struct sockaddr_in *sin;
sin = (struct sockaddr_in *)addr;
return sin->sin_addr;
}
struct in6_addr get_inet6_ip(struct sockaddr_storage *addr) {
struct sockaddr_in6 *sin6;
sin6 = (struct sockaddr_in6 *)addr;
return sin6->sin6_addr;
}
uint8_t get_inet4_port(struct sockaddr_storage *addr) {
struct sockaddr_in *sin;
sin = (struct sockaddr_in *)addr;
return sin->sin_port;
}
uint16_t get_inet6_port(struct sockaddr_storage *addr) {
struct sockaddr_in6 *sin6;
sin6 = (struct sockaddr_in6 *)addr;
return sin6->sin6_port;
}
static char * pp_strtok(char *str, const char *sep, char **last) {
char *token;
if (!str) /* subsequent call */
str = *last; /* start where we left off */
/* skip characters in sep (will terminate at '\0') */
while (*str && strchr(sep, *str))
++str;
if (!*str) /* no more tokens */
return NULL;
token = str;
/* skip valid token characters to terminate token and
* prepare for the next call (will terminate at '\0)
* */
*last = token + 1;
while (**last && !strchr(sep, **last))
++*last;
if (**last) {
**last = '\0';
++*last;
}
return token;
}
/* proxy_ptc_v1_encode() : encode a proxy protocol header based
* on v1 specification
* I/P
* buf : buffer where encoded header will be
* placed
* len : total length of the header
* src : src address
* dst : dst address
*
* O/P
* return : 0 if success else errors in pp_ret_t
*/
pp_ret_t proxy_ptc_v1_encode(char *buf, int8_t *len,
struct sockaddr_storage *src,
struct sockaddr_storage *dst) {
uint8_t fam;
fam = get_addr_family(dst);
switch(fam) {
case AF_INET: /* TCPv4 */
sprintf(buf, "PROXY TCP4 %s %s %d %d", inet_ntoa(get_inet4_ip(src)),
inet_ntoa(get_inet4_ip(dst)),
get_inet4_port(src),
get_inet4_port(dst));
*len = strlen(buf);
// put terminating char '\r\n'
buf[*len] = '\r';
buf[*len + 1] = '\n';
*len = *len + 2;
break;
case AF_INET6: /* TCPv6 */
*len = 0;
break;
default:
return PPINVALFAM;
}
return PPNOERR;
}
/* proxy_ptc_v2_encode() : encode a proxy protocol header based
* on v2 specification
* I/P
* buf : buffer where encoded header will be
* placed
* len : total length of the header
* src : src address
* dst : dst address
*
* O/P
* return : 0 if success else errors in pp_ret_t
*/
pp_ret_t proxy_ptc_v2_encode(char *buf, int8_t *len,
struct sockaddr_storage *src,
struct sockaddr_storage *dst) {
uint8_t fam;
pproxy_v2_t *pp_hdr;
memcpy(pp_hdr->sig, v2sig, sizeof(pp_hdr->sig));
pp_hdr->ver_cmd = vercmd;
fam = get_addr_family(dst);
switch(fam) {
case AF_INET: /* TCPv4 */
pp_hdr->fam = 0x11;
pp_hdr->len = htons(IPV4_ADDR_LEN);
pp_hdr->addr.ip4.src_addr = (get_inet4_ip(src)).s_addr;
pp_hdr->addr.ip4.dst_addr = (get_inet4_ip(dst)).s_addr;
pp_hdr->addr.ip4.src_port = htons(get_inet4_port(src));
pp_hdr->addr.ip4.dst_port = htons(get_inet4_port(dst));
*len = V2_HDR_LEN + IPV4_ADDR_LEN;
break;
case AF_INET6: /* TCPv6 */
*len = 0;
break;
default:
return PPINVALFAM;
}
return PPNOERR;
}
/* proxy_ptc_send() : encode a proxy protocol header based
* on provided version and send into socket
* I/P
* fd : socket file descriptor
* ppver : protocol proxy version
* src : src address
* dst : dst address
*
* O/P
* return : 0 if success else errors in pp_ret_t
*/
pp_ret_t proxy_ptc_send(int fd,
pproxy_ver_t ppver,
struct sockaddr_storage *src,
struct sockaddr_storage *dst) {
char pktbuf[MAX_PP_LEN];
int8_t len;
int ret, n, totalw, serrno;
switch(ppver) {
case PPROXY_V1:
ret = proxy_ptc_v1_encode(pktbuf, &len, src, dst);
break;
case PPROXY_V2:
ret = proxy_ptc_v2_encode(pktbuf, &len, src, dst);
}
if (ret != PPNOERR) {
return ret;
}
while(1) {
n = send(fd, pktbuf + totalw, len - totalw, 0);
serrno = errno;
if (n > 0) {
totalw += n;
if(totalw == (ssize_t)len)
break;
else
continue;
} else if (n ==0) {
continue;
} else {
if(serrno == EINTR) {
continue;
} else if (serrno == EAGAIN) { // we continue if busy
continue;
} else {
errno = serrno;
return PPSENDERR;
}
}
}
return PPNOERR;
}
/* proxy_ptc_decode() : decode a proxy protocol header from
* provided pkt buffer
* I/P
* buf : buffer where pkt has been received
* len : total length of the pkt
* ppver : ppver to set the version received
* src : src address to fill the src addr
* dst : dst address to fill the dest addr
*
* O/P
* return : total header size if success else
* errors in pp_ret_t
*/
pp_ret_t proxy_ptc_decode(char *buf, int len,
pproxy_ver_t *ppver,
struct sockaddr_storage *src,
struct sockaddr_storage *dst) {
int size;
pproxy_hdr_t *hdr;
hdr = (pproxy_hdr_t *)buf;
if(len >= V2_HDR_LEN && memcmp(&hdr->v2, v2sig, 12) == 0 &&
(hdr->v2.ver_cmd & 0xF0) == 0x20) {
*ppver = PPROXY_V2;
size = 16 + ntohs(hdr->v2.len);
if (len < size) {
return PPTRUNCATED;
}
switch(hdr->v2.ver_cmd & 0xF) {
case 0x01: /* PROXY command */
switch(hdr->v2.fam) {
case 0x11: /* TCPv4 */
((struct sockaddr_in *)src)->sin_family = AF_INET;
((struct sockaddr_in *)src)->sin_addr.s_addr =
hdr->v2.addr.ip4.src_addr;
((struct sockaddr_in *)src)->sin_port =
ntohs(hdr->v2.addr.ip4.src_port);
((struct sockaddr_in *)dst)->sin_family = AF_INET;
((struct sockaddr_in *)dst)->sin_addr.s_addr =
hdr->v2.addr.ip4.dst_addr;
((struct sockaddr_in *)dst)->sin_port =
ntohs(hdr->v2.addr.ip4.dst_port);
break;
case 0x21: /* TCPv6 */
((struct sockaddr_in6 *)src)->sin6_family = AF_INET6;
memcpy(&((struct sockaddr_in6 *)src)->sin6_addr,
hdr->v2.addr.ip6.src_addr, 16);
((struct sockaddr_in6 *)src)->sin6_port =
ntohs(hdr->v2.addr.ip6.src_port);
((struct sockaddr_in6 *)dst)->sin6_family = AF_INET6;
memcpy(&((struct sockaddr_in6 *)dst)->sin6_addr,
hdr->v2.addr.ip6.dst_addr, 16);
((struct sockaddr_in6 *)dst)->sin6_port =
ntohs(hdr->v2.addr.ip6.dst_port);
break;
}
break;
case 0x00: /* LOCAL command */
return PPLOCALCMD;
default:
return PPINVALCMD;
}
} else if (len >= 8 && memcmp(hdr->v1.line, "PROXY", 5) == 0) {
char *end = memchr(hdr->v1.line, '\r', len - 1);
char buf[sizeof(hdr->v1.line)];
char *word, *saveptr, *valid_addr_chars, *srcip, *dstip;
uint16_t srcport, dstport;
int family;
*ppver = PPROXY_V1;
if (!end || end[1] != '\n')
return PPTRUNCATED;
*end = '\0';
size = end + 2 - hdr->v1.line;
strcpy(buf, hdr->v1.line);
pp_strtok(buf, " ", &saveptr);
GET_NEXT_WORD()
if (strcmp(word, "UNKNOWN") == 0) { /* LOCAL command */
return PPLOCALCMD;
}
else if (strcmp(word, "TCP4") == 0) {
family = AF_INET;
valid_addr_chars = "0123456789.";
}
else if (strcmp(word, "TCP6") == 0) {
family = AF_INET6;
valid_addr_chars = "0123456789abcdefABCDEF:";
}
else {
return PPHDRERR;
}
GET_NEXT_WORD()
if (strspn(word, valid_addr_chars) != strlen(word)) {
return PPINVALADDR;
}
srcip = word;
GET_NEXT_WORD()
if (strspn(word, valid_addr_chars) != strlen(word)) {
return PPINVALADDR;
}
dstip = word;
GET_NEXT_WORD()
if (sscanf(word, "%hu", &srcport) != 1) {
return PPHDRERR;
}
GET_NEXT_WORD()
if (sscanf(word, "%hu", &dstport) != 1) {
return PPHDRERR;
}
switch(family) {
case AF_INET:
((struct sockaddr_in *)src)->sin_family = AF_INET;
inet_pton(AF_INET, srcip, &(((struct sockaddr_in *)src)->sin_addr));
((struct sockaddr_in *)src)->sin_port = (uint8_t)srcport;
((struct sockaddr_in *)dst)->sin_family = AF_INET;
inet_pton(AF_INET, dstip, &(((struct sockaddr_in *)dst)->sin_addr));
((struct sockaddr_in *)dst)->sin_port = (uint8_t)dstport;
break;
case AF_INET6:
((struct sockaddr_in6 *)src)->sin6_family = AF_INET6;
inet_pton(AF_INET6, srcip, &(((struct sockaddr_in6 *)src)->sin6_addr));
((struct sockaddr_in6 *)src)->sin6_port = srcport;
((struct sockaddr_in6 *)dst)->sin6_family = AF_INET6;
inet_pton(AF_INET6, dstip, &(((struct sockaddr_in6 *)dst)->sin6_addr));
((struct sockaddr_in6 *)dst)->sin6_port = dstport;
}
} else {
/* invalid protocol */
return PPHDRERR;
}
return size;
}
/* proxy_ptc_read() : read packet and decode a proxy protocol
* header from provided sock fd
* I/P
* fd : the file desc to read from
* ppver : ppver to set the version received
* src : src address to fill the src addr
* dst : dst address to fill the dest addr
*
* O/P
* return : 0 if success else errors in pp_ret_t
*/
pp_ret_t proxy_ptc_read(int fd,
pproxy_ver_t *ppver,
struct sockaddr_storage *src,
struct sockaddr_storage *dst) {
int ret;
pproxy_hdr_t hdr;
do {
ret = recv(fd, &hdr, sizeof(hdr), MSG_PEEK);
} while (ret == -1 && errno == EINTR);
if (ret == -1)
return (errno == EAGAIN) ? EAGAIN : PPREADERR;
ret = proxy_ptc_decode((char *)&hdr, ret, ppver, src, dst);
if (ret > 0) {
do {
// we need to consume the appropriate
// amount of data from the socket
ret = recv(fd, &hdr, ret, 0);
} while (ret == -1 && errno == EINTR);
return (ret >= 0) ? PPNOERR : PPREADERR;
}
return ret;
}