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ggsn: Parse PCO_IPCP 

Improvements include:
- Use Identifier received from request instead of using hardcoded id=0.
- Don't add DNS to response if they were not included in request.

Change-Id: Ic8aa5d634e526683b2ad8ed5d14088e171c41c98
This commit is contained in:
Pau Espin 2018-01-26 17:46:37 +01:00 committed by Harald Welte
parent 5b1ef9589c
commit 0bdd8bf5bc
1 changed files with 53 additions and 15 deletions
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68
ggsn/ggsn.c
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@ -377,6 +377,41 @@ static int delete_context(struct pdp_t *pdp)
#include <osmocom/gsm/tlv.h>
/* RFC 1332 */
enum ipcp_options {
IPCP_OPT_IPADDR = 3,
IPCP_OPT_PRIMARY_DNS = 129,
IPCP_OPT_SECONDARY_DNS = 131,
};
struct ipcp_option_hdr {
uint8_t type;
uint8_t len;
uint8_t data[0];
};
struct ipcp_hdr {
uint8_t code;
uint8_t id;
uint16_t len;
uint8_t options[0];
};
/* determine if IPCP contains given option */
static struct ipcp_option_hdr *ipcp_contains_option(struct ipcp_hdr *ipcp, enum ipcp_options opt)
{
uint8_t *cur = ipcp->options;
/* iterate over Options and check if protocol contained */
while (cur + 2 <= ((uint8_t *)ipcp) + ipcp->len) {
struct ipcp_option_hdr *cur_opt = (struct ipcp_option_hdr *) cur;
if (cur_opt->type == opt)
return cur_opt;
cur += cur_opt->len;
}
return NULL;
}
/* 3GPP TS 24.008 10.6.5.3 */
enum pco_protocols {
PCO_P_LCP = 0xC021,
@ -410,7 +445,7 @@ enum pco_protocols {
};
/* determine if PCO contains given protocol */
static bool pco_contains_proto(struct ul255_t *pco, uint16_t prot)
static uint8_t *pco_contains_proto(struct ul255_t *pco, uint16_t prot)
{
uint8_t *cur = pco->v + 1;
@ -419,10 +454,10 @@ static bool pco_contains_proto(struct ul255_t *pco, uint16_t prot)
uint16_t cur_prot = osmo_load16be(cur);
uint8_t cur_len = cur[2];
if (cur_prot == prot)
return true;
return cur;
cur += cur_len + 3;
}
return false;
return NULL;
}
/*! Get the peer of pdp based on IP version used.
@ -458,30 +493,36 @@ static bool pdp_has_v4(struct pdp_t *pdp)
return false;
}
/* construct an IPCP PCO from up to two given DNS addreses */
static int build_ipcp_pco(struct msgb *msg, uint8_t id, const struct in46_addr *dns1,
const struct in46_addr *dns2)
/* construct an IPCP PCO response from request*/
static int build_ipcp_pco(struct apn_ctx *apn, struct pdp_t *pdp, struct msgb *msg)
{
uint8_t *len1, *len2;
const struct in46_addr *dns1 = &apn->v4.cfg.dns[0];
const struct in46_addr *dns2 = &apn->v4.cfg.dns[1];
struct ipcp_hdr *ipcp;
uint8_t *len1, *len2, *pco_ipcp;
uint8_t *start = msg->tail;
unsigned int len_appended;
if (!(pco_ipcp = pco_contains_proto(&pdp->pco_req, PCO_P_IPCP)))
return 0;
ipcp = (struct ipcp_hdr*) (pco_ipcp + 3); /* 2=type + 1=len */
/* Three byte T16L header */
msgb_put_u16(msg, 0x8021); /* IPCP */
len1 = msgb_put(msg, 1); /* Length of contents: delay */
msgb_put_u8(msg, 0x02); /* ACK */
msgb_put_u8(msg, id); /* ID: Needs to match request */
msgb_put_u8(msg, ipcp->id); /* ID: Needs to match request */
msgb_put_u8(msg, 0x00); /* Length MSB */
len2 = msgb_put(msg, 1); /* Length LSB: delay */
if (dns1 && dns1->len == 4) {
if (dns1->len == 4 && ipcp_contains_option(ipcp, IPCP_OPT_PRIMARY_DNS)) {
msgb_put_u8(msg, 0x81); /* DNS1 Tag */
msgb_put_u8(msg, 2 + dns1->len);/* DNS1 Length, incl. TL */
msgb_put_u32(msg, ntohl(dns1->v4.s_addr));
}
if (dns2 && dns2->len == 4) {
if (dns2->len == 4 && ipcp_contains_option(ipcp, IPCP_OPT_SECONDARY_DNS)) {
msgb_put_u8(msg, 0x83); /* DNS2 Tag */
msgb_put_u8(msg, 2 + dns2->len);/* DNS2 Length, incl. TL */
msgb_put_u32(msg, ntohl(dns2->v4.s_addr));
@ -504,11 +545,8 @@ static void process_pco(struct apn_ctx *apn, struct pdp_t *pdp)
OSMO_ASSERT(msg);
msgb_put_u8(msg, 0x80); /* ext-bit + configuration protocol byte */
/* FIXME: also check if primary / secondary DNS was requested */
if (pdp_has_v4(pdp) && pco_contains_proto(&pdp->pco_req, PCO_P_IPCP)) {
/* FIXME: properly implement this for IPCP */
build_ipcp_pco(msg, 0, &apn->v4.cfg.dns[0], &apn->v4.cfg.dns[1]);
}
if (pdp_has_v4(pdp))
build_ipcp_pco(apn, pdp, msg);
if (pco_contains_proto(&pdp->pco_req, PCO_P_DNS_IPv6_ADDR)) {
for (i = 0; i < ARRAY_SIZE(apn->v6.cfg.dns); i++) {