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gnrc_icmpv6_error: adapt _fit() to get MTU from netif

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This commit is contained in:
Martine Lenders 2018-11-14 14:37:40 +01:00
parent c8c8564d51
commit c4175a5e52
1 changed files with 32 additions and 4 deletions
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36
sys/net/gnrc/network_layer/icmpv6/error/gnrc_icmpv6_error.c
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@ -26,13 +26,41 @@
#define ICMPV6_ERROR_SET_VALUE(data, value) \
((icmpv6_error_pkt_too_big_t *)(data))->mtu = byteorder_htonl(value)
/* TODO: generalize and centralize (see https://github.com/RIOT-OS/RIOT/pull/3184) */
#define MIN(a, b) ((a) < (b)) ? (a) : (b)
static inline size_t _fit(const gnrc_pktsnip_t *pkt)
/**
* @brief Get packet fit.
*
* Get's the minimum size for an ICMPv6 error message packet, based on the
* invoking packet's size and the interface the invoking packet came over.
*
* @param[in] orig_pkt The invoking packet
*
* @return The supposed size of the ICMPv6 error message.
*/
static size_t _fit(const gnrc_pktsnip_t *orig_pkt)
{
/* TODO: replace IPV6_MIN_MTU with known path MTU? */
return MIN((gnrc_pkt_len(pkt) + ICMPV6_ERROR_SZ), IPV6_MIN_MTU);
/* discarding const qualifier is safe here */
gnrc_pktsnip_t *netif_hdr = gnrc_pktsnip_search_type(
(gnrc_pktsnip_t *)orig_pkt, GNRC_NETTYPE_NETIF
);
size_t pkt_len = gnrc_pkt_len(orig_pkt) + ICMPV6_ERROR_SZ +
sizeof(ipv6_hdr_t);
if (netif_hdr) {
gnrc_netif_hdr_t *data = netif_hdr->data;
gnrc_netif_t *netif = gnrc_netif_get_by_pid(data->if_pid);
DEBUG("gnrc_icmpv6_error: fitting to MTU of iface %u (%u)\n",
netif->pid, netif->ipv6.mtu);
return MIN(pkt_len, netif->ipv6.mtu - sizeof(ipv6_hdr_t));
}
else {
/* packet does not have a netif header (most likely because it did not
* came from remote) => just assume pkt_len as ideal */
DEBUG("gnrc_icmpv6_error: copying whole packet\n");
return pkt_len;
}
}
/* Build a generic error message */