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feat: Support more addresses in RDNSS section #245

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merged 1 commit into from
Dec 30, 2024
Merged

feat: Support more addresses in RDNSS section #245

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4 changes: 1 addition & 3 deletions defaults.h
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Original file line number Diff line number Diff line change
Expand Up @@ -205,9 +205,7 @@ struct nd_opt_rdnss_info_local {
uint8_t nd_opt_rdnssi_len;
uint16_t nd_opt_rdnssi_pref_flag_reserved;
uint32_t nd_opt_rdnssi_lifetime;
struct in6_addr nd_opt_rdnssi_addr1;
struct in6_addr nd_opt_rdnssi_addr2;
struct in6_addr nd_opt_rdnssi_addr3;
struct in6_addr nd_opt_rdnssi_addr[];
};
/* pref/flag/reserved field : yyyyx00000000000 (big endian) - 00000000yyyyx000 (little indian); where yyyy = pref, x = flag */
#if BYTE_ORDER == BIG_ENDIAN
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30 changes: 13 additions & 17 deletions gram.y
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Original file line number Diff line number Diff line change
Expand Up @@ -847,24 +847,19 @@ rdnssaddr : IPV6ADDR
rdnss_init_defaults(rdnss, iface);
}

switch (rdnss->AdvRDNSSNumber) {
case 0:
memcpy(&rdnss->AdvRDNSSAddr1, $1, sizeof(struct in6_addr));
rdnss->AdvRDNSSNumber++;
break;
case 1:
memcpy(&rdnss->AdvRDNSSAddr2, $1, sizeof(struct in6_addr));
rdnss->AdvRDNSSNumber++;
break;
case 2:
memcpy(&rdnss->AdvRDNSSAddr3, $1, sizeof(struct in6_addr));
rdnss->AdvRDNSSNumber++;
break;
default:
flog(LOG_CRIT, "too many addresses in RDNSS section");
ABORT;
rdnss->AdvRDNSSNumber++;
if (rdnss->AdvRDNSSNumber > 127) {
flog(LOG_CRIT, "Too many RDNSS servers specified - upper limit is 127 based on RDNSSI length field being uint8, RFC8106, section 5.1");
ABORT;
}

rdnss->AdvRDNSSAddr =
realloc(rdnss->AdvRDNSSAddr,
rdnss->AdvRDNSSNumber * sizeof(struct in6_addr));
if (rdnss->AdvRDNSSAddr == NULL) {
flog(LOG_CRIT, "realloc failed: %s", strerror(errno));
ABORT;
}
memcpy(&rdnss->AdvRDNSSAddr[rdnss->AdvRDNSSNumber - 1], $1, sizeof(struct in6_addr));
}
;

Expand Down Expand Up @@ -1127,6 +1122,7 @@ static void cleanup(void)
}

if (rdnss) {
free(rdnss->AdvRDNSSAddr);
free(rdnss);
rdnss = 0;
}
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1 change: 1 addition & 0 deletions interface.c
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Original file line number Diff line number Diff line change
Expand Up @@ -420,6 +420,7 @@ static void free_iface_list(struct Interface *iface)
while (rdnss) {
struct AdvRDNSS *next_rdnss = rdnss->next;

free(rdnss->AdvRDNSSAddr);
free(rdnss);
rdnss = next_rdnss;
}
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47 changes: 13 additions & 34 deletions process.c
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Original file line number Diff line number Diff line change
Expand Up @@ -322,44 +322,23 @@ static void process_ra(struct Interface *iface, unsigned char *msg, int len, str
break;
case ND_OPT_RDNSS_INFORMATION: {
char rdnss_str[INET6_ADDRSTRLEN];
struct AdvRDNSS *rdnss = 0;
struct nd_opt_rdnss_info_local *rdnssinfo = (struct nd_opt_rdnss_info_local *)opt_str;
if (len < sizeof(*rdnssinfo))
return;
int count = rdnssinfo->nd_opt_rdnssi_len;

/* Check the RNDSS addresses received */
switch (count) {
case 7:
rdnss = iface->AdvRDNSSList;
if (!check_rdnss_presence(rdnss, &rdnssinfo->nd_opt_rdnssi_addr3)) {
/* no match found in iface->AdvRDNSSList */
addrtostr(&rdnssinfo->nd_opt_rdnssi_addr3, rdnss_str, sizeof(rdnss_str));
flog(LOG_WARNING, "RDNSS address %s received on %s from %s is not advertised by us",
rdnss_str, iface->props.name, addr_str);
}
/* FALLTHROUGH */
case 5:
rdnss = iface->AdvRDNSSList;
if (!check_rdnss_presence(rdnss, &rdnssinfo->nd_opt_rdnssi_addr2)) {
/* no match found in iface->AdvRDNSSList */
addrtostr(&rdnssinfo->nd_opt_rdnssi_addr2, rdnss_str, sizeof(rdnss_str));
flog(LOG_WARNING, "RDNSS address %s received on %s from %s is not advertised by us",
rdnss_str, iface->props.name, addr_str);
}
/* FALLTHROUGH */
case 3:
rdnss = iface->AdvRDNSSList;
if (!check_rdnss_presence(rdnss, &rdnssinfo->nd_opt_rdnssi_addr1)) {
/* no match found in iface->AdvRDNSSList */
addrtostr(&rdnssinfo->nd_opt_rdnssi_addr1, rdnss_str, sizeof(rdnss_str));
flog(LOG_WARNING, "RDNSS address %s received on %s from %s is not advertised by us",
rdnss_str, iface->props.name, addr_str);
}

break;
default:
flog(LOG_ERR, "invalid len %i in RDNSS option on %s from %s", count, iface->props.name, addr_str);
// must be a multiple of 2, in the range of 3..255
// https://datatracker.ietf.org/doc/html/rfc8106#section-5.1
if (rdnssinfo->nd_opt_rdnssi_len >= 3 && rdnssinfo->nd_opt_rdnssi_len % 2 == 1) {
for (int i = 0; i < (rdnssinfo->nd_opt_rdnssi_len - 1) / 2; i++) {
if (!check_rdnss_presence(iface->AdvRDNSSList, &rdnssinfo->nd_opt_rdnssi_addr[i])) {
addrtostr(&rdnssinfo->nd_opt_rdnssi_addr[i], rdnss_str, sizeof(rdnss_str));
flog(LOG_WARNING, "RDNSS address %s received on %s from %s is not advertised by us",
rdnss_str, iface->props.name, addr_str);
}
}
} else {
flog(LOG_ERR, "invalid len %i in RDNSS option on %s from %s",
rdnssinfo->nd_opt_rdnssi_len, iface->props.name, addr_str);
}

break;
Expand Down
4 changes: 1 addition & 3 deletions radvd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -208,9 +208,7 @@ struct AdvRDNSS {
int AdvRDNSSNumber;
uint32_t AdvRDNSSLifetime;
int FlushRDNSSFlag;
struct in6_addr AdvRDNSSAddr1;
struct in6_addr AdvRDNSSAddr2;
struct in6_addr AdvRDNSSAddr3;
struct in6_addr *AdvRDNSSAddr;

struct AdvRDNSS *next;
};
Expand Down
35 changes: 16 additions & 19 deletions radvdump.c
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Original file line number Diff line number Diff line change
Expand Up @@ -400,28 +400,25 @@ static void print_ff(unsigned char *msg, int len, struct sockaddr_in6 *addr, int
case ND_OPT_RDNSS_INFORMATION: {
struct nd_opt_rdnss_info_local *rdnss_info = (struct nd_opt_rdnss_info_local *)opt_str;

printf("\n\tRDNSS");

addrtostr(&rdnss_info->nd_opt_rdnssi_addr1, prefix_str, sizeof(prefix_str));
printf(" %s", prefix_str);

if (rdnss_info->nd_opt_rdnssi_len >= 5) {
addrtostr(&rdnss_info->nd_opt_rdnssi_addr2, prefix_str, sizeof(prefix_str));
printf(" %s", prefix_str);
}
if (rdnss_info->nd_opt_rdnssi_len >= 7) {
addrtostr(&rdnss_info->nd_opt_rdnssi_addr3, prefix_str, sizeof(prefix_str));
printf(" %s", prefix_str);
if (rdnss_info->nd_opt_rdnssi_len >= 3 && rdnss_info->nd_opt_rdnssi_len % 2 == 1) {
printf("\n\tRDNSS");
for (int i = 0; i < (rdnss_info->nd_opt_rdnssi_len - 1) / 2; i++) {
addrtostr(&rdnss_info->nd_opt_rdnssi_addr[i], prefix_str, sizeof(prefix_str));
printf(" %s", prefix_str);
}
printf("\n\t{\n");
/* as AdvRDNSSLifetime may depend on MaxRtrAdvInterval, it could change */
if (ntohl(rdnss_info->nd_opt_rdnssi_lifetime) == 0xffffffff)
printf("\t\tAdvRDNSSLifetime infinity; # (0xffffffff)\n");
else
printf("\t\tAdvRDNSSLifetime %u;\n", ntohl(rdnss_info->nd_opt_rdnssi_lifetime));
printf("\t}; # End of RDNSS definition\n\n");
} else {
flog(LOG_ERR, "Invalid RDNSS option length %d from %s", rdnss_info->nd_opt_rdnssi_len, addr_str);
printf("# Invalid RDNSS length %d, per RFC8106 section 5.1 ", rdnss_info->nd_opt_rdnssi_len);
}

printf("\n\t{\n");
/* as AdvRDNSSLifetime may depend on MaxRtrAdvInterval, it could change */
if (ntohl(rdnss_info->nd_opt_rdnssi_lifetime) == 0xffffffff)
printf("\t\tAdvRDNSSLifetime infinity; # (0xffffffff)\n");
else
printf("\t\tAdvRDNSSLifetime %u;\n", ntohl(rdnss_info->nd_opt_rdnssi_lifetime));

printf("\t}; # End of RDNSS definition\n\n");
break;
}
case ND_OPT_DNSSL_INFORMATION: {
Expand Down
23 changes: 16 additions & 7 deletions send.c
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Original file line number Diff line number Diff line change
Expand Up @@ -602,14 +602,23 @@ static struct safe_buffer_list *add_ra_options_rdnss(struct safe_buffer_list *sb
{
while (rdnss) {
struct nd_opt_rdnss_info_local rdnssinfo;

if (!cease_adv && !schedule_option_rdnss(dest, iface, rdnss)) {
rdnss = rdnss->next;
continue;
}

memset(&rdnssinfo, 0, sizeof(rdnssinfo));

size_t const bytes = sizeof(rdnssinfo) + sizeof(struct in6_addr) * rdnss->AdvRDNSSNumber;
// dnsslinfo.nd_opt_rdnssi_len is uint8 count of 8-octet groups; min 3, max 255
// too many DNS servers could exceed it
// https://datatracker.ietf.org/doc/html/rfc8106#section-5.1
if (bytes > (255 * 8)) {
flog(LOG_ERR, "RDNSS too long for RA option, must be < 2032 bytes. Skipping option.");
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Same comment as the other PR - shouldn't this be <= 2040 bytes? Or am I not understanding the math?

rdnss = rdnss->next;
continue;
}

rdnssinfo.nd_opt_rdnssi_type = ND_OPT_RDNSS_INFORMATION;
rdnssinfo.nd_opt_rdnssi_len = 1 + 2 * rdnss->AdvRDNSSNumber;
rdnssinfo.nd_opt_rdnssi_pref_flag_reserved = 0;
Expand All @@ -620,13 +629,13 @@ static struct safe_buffer_list *add_ra_options_rdnss(struct safe_buffer_list *sb
rdnssinfo.nd_opt_rdnssi_lifetime = htonl(rdnss->AdvRDNSSLifetime);
}

memcpy(&rdnssinfo.nd_opt_rdnssi_addr1, &rdnss->AdvRDNSSAddr1, sizeof(struct in6_addr));
memcpy(&rdnssinfo.nd_opt_rdnssi_addr2, &rdnss->AdvRDNSSAddr2, sizeof(struct in6_addr));
memcpy(&rdnssinfo.nd_opt_rdnssi_addr3, &rdnss->AdvRDNSSAddr3, sizeof(struct in6_addr));

sbl = safe_buffer_list_append(sbl);
safe_buffer_append(sbl->sb, &rdnssinfo,
sizeof(rdnssinfo) - (3 - rdnss->AdvRDNSSNumber) * sizeof(struct in6_addr));
safe_buffer_resize(sbl->sb, sbl->sb->used + bytes);
safe_buffer_append(sbl->sb, &rdnssinfo, sizeof(rdnssinfo));
for (int i = 0; i < rdnss->AdvRDNSSNumber; i++) {
safe_buffer_append(sbl->sb, &rdnss->AdvRDNSSAddr[i], sizeof(struct in6_addr));
}
// padding is only required for DNSSL

rdnss = rdnss->next;
}
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8 changes: 4 additions & 4 deletions util.c
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Original file line number Diff line number Diff line change
Expand Up @@ -191,10 +191,10 @@ void addrtostr(struct in6_addr const *addr, char *str, size_t str_size)
int check_rdnss_presence(struct AdvRDNSS *rdnss, struct in6_addr *addr)
{
while (rdnss) {
if (!memcmp(&rdnss->AdvRDNSSAddr1, addr, sizeof(struct in6_addr)) ||
!memcmp(&rdnss->AdvRDNSSAddr2, addr, sizeof(struct in6_addr)) ||
!memcmp(&rdnss->AdvRDNSSAddr3, addr, sizeof(struct in6_addr)))
return 1; /* rdnss address found in the list */
for (int i = 0; i < rdnss->AdvRDNSSNumber; i++) {
if (!memcmp(&rdnss->AdvRDNSSAddr[i], addr, sizeof(struct in6_addr)))
return 1; /* rdnss address found in the list */
}
rdnss = rdnss->next;
}
return 0;
Expand Down
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