From: Andrew <and...@daynix.com>
The basic IPv6 fragmentation - adding 'frag' extension to
the packet, overall shares some logic with IPv4. It works,
but there are still issues with a combination of
extensions - in the future, it would require refactoring
work to implement workflow with IPv6 and extension.
"Jumbo option" isn't added yet, until
qemu supports packets greater than 64K.
Signed-off-by: Andrew Melnychenko <and...@daynix.com>
---
hw/net/net_tx_pkt.c | 7 ++--
include/net/eth.h | 14 +++++--
net/eth.c | 99 ++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 109 insertions(+), 11 deletions(-)
diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 9560e4a49e..74044c6618 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -589,10 +589,11 @@ static bool net_tx_pkt_do_sw_fragmentation(struct
NetTxPkt *pkt,
more_frags = (fragment_offset + fragment_len < pkt->payload_len);
- eth_setup_ip4_fragmentation(l2_iov_base, l2_iov_len, l3_iov_base,
- l3_iov_len, fragment_len, fragment_offset, more_frags);
+ eth_setup_ip_fragmentation(l2_iov_base, l2_iov_len, l3_iov_base,
+ &l3_iov_len, ETH_MAX_IP_DGRAM_LEN,
+ fragment_len, fragment_offset, more_frags);
- eth_fix_ip4_checksum(l3_iov_base, l3_iov_len);
+ fragment[NET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_len = l3_iov_len;
net_tx_pkt_sendv(pkt, nc, fragment, dst_idx);
diff --git a/include/net/eth.h b/include/net/eth.h
index 0671be6916..05c75ac9fc 100644
--- a/include/net/eth.h
+++ b/include/net/eth.h
@@ -139,6 +139,14 @@ struct ip6_ext_hdr_routing {
uint8_t rsvd[4];
};
+struct ip6_ext_hdr_fragment {
+ uint8_t nxt;
+ uint8_t res0;
+ uint16_t off;
+ uint32_t id;
+};
+
+
struct ip6_option_hdr {
#define IP6_OPT_PAD1 (0x00)
#define IP6_OPT_HOME (0xC9)
@@ -399,9 +407,9 @@ void eth_get_protocols(const struct iovec *iov, int iovcnt,
eth_ip4_hdr_info *ip4hdr_info,
eth_l4_hdr_info *l4hdr_info);
-void eth_setup_ip4_fragmentation(const void *l2hdr, size_t l2hdr_len,
- void *l3hdr, size_t l3hdr_len,
- size_t l3payload_len,
+void eth_setup_ip_fragmentation(const void *l2hdr, size_t l2hdr_len,
+ void *l3hdr, size_t *l3hdr_len,
+ size_t l3hdr_max_len, size_t l3payload_len,
size_t frag_offset, bool more_frags);
void
diff --git a/net/eth.c b/net/eth.c
index 0c1d413ee2..067111526d 100644
--- a/net/eth.c
+++ b/net/eth.c
@@ -314,10 +314,65 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt,
size_t iovoff,
return 0;
}
+static bool eth_is_ip6_extension_header_type(uint8_t hdr_type);
+
+static void *eth_ip6_find_ext(struct ip6_header *ip6, uint8_t ext_type)
+{
+ uint8_t curr_ext_hdr_type = ip6->ip6_nxt;
+ struct ip6_ext_hdr *ext_hdr = (struct ip6_ext_hdr *)(ip6 + 1);
+ for (; eth_is_ip6_extension_header_type(curr_ext_hdr_type);) {
+ if (curr_ext_hdr_type == ext_type) {
+ return ext_hdr;
+ }
+ curr_ext_hdr_type = ext_hdr->ip6r_nxt;
+ ext_hdr = (struct ip6_ext_hdr *)(((uint8_t *)ext_hdr)
+ + (ext_hdr->ip6r_len + 1) * IP6_EXT_GRANULARITY);
+ }
+
+ return NULL;
+}
+
+/*
+ * To add an extension - there is should be
+ * enough memory 'behind' the ip6 header.
+ */
+static void *eth_ip6_add_ext_nonsafe(struct ip6_header *ip6, uint8_t ext_type)
+{
+ uint8_t curr_ext_hdr_type = ip6->ip6_nxt;
+ struct ip6_ext_hdr *ext_hdr = (struct ip6_ext_hdr *)(ip6 + 1);
+ struct ip6_ext_hdr *ext_hdr_prev = NULL;
+
+ if (!eth_is_ip6_extension_header_type(curr_ext_hdr_type)) {
+ ext_hdr->ip6r_nxt = ip6->ip6_nxt;
+ ip6->ip6_nxt = ext_type;
+ return ext_hdr;
+ }
+
+ ext_hdr_prev = ext_hdr;
+ curr_ext_hdr_type = ext_hdr->ip6r_nxt;
+ ext_hdr = (struct ip6_ext_hdr *)(((uint8_t *)ext_hdr)
+ + (ext_hdr->ip6r_len + 1) * IP6_EXT_GRANULARITY);
+
+ for (; eth_is_ip6_extension_header_type(curr_ext_hdr_type);) {
+ ext_hdr_prev = ext_hdr;
+ curr_ext_hdr_type = ext_hdr->ip6r_nxt;
+ ext_hdr = (struct ip6_ext_hdr *)(((uint8_t *)ext_hdr)
+ + (ext_hdr->ip6r_len + 1) * IP6_EXT_GRANULARITY);
+ }
+
+ ext_hdr->ip6r_nxt = ext_hdr_prev->ip6r_nxt;
+ ext_hdr_prev->ip6r_nxt = ext_type;
+
+ return ext_hdr;
+}
+
+/* When IP6_FRAGMENT added, first 'id' would be 0x71656d75 */
+static const uint32_t s_first_fragment_identificator = 0x71656d75; /* 'qemu' */
+
void
-eth_setup_ip4_fragmentation(const void *l2hdr, size_t l2hdr_len,
- void *l3hdr, size_t l3hdr_len,
- size_t l3payload_len,
+eth_setup_ip_fragmentation(const void *l2hdr, size_t l2hdr_len,
+ void *l3hdr, size_t *l3hdr_len,
+ size_t l3hdr_max_len, size_t l3payload_len,
size_t frag_offset, bool more_frags)
{
const struct iovec l2vec = {
@@ -325,7 +380,9 @@ eth_setup_ip4_fragmentation(const void *l2hdr, size_t
l2hdr_len,
.iov_len = l2hdr_len
};
- if (eth_get_l3_proto(&l2vec, 1, l2hdr_len) == ETH_P_IP) {
+ uint16_t l3_proto = eth_get_l3_proto(&l2vec, 1, l2hdr_len);
+
+ if (l3_proto == ETH_P_IP) {
uint16_t orig_flags;
struct ip_header *iphdr = (struct ip_header *) l3hdr;
uint16_t frag_off_units = frag_offset / IP_FRAG_UNIT_SIZE;
@@ -337,7 +394,39 @@ eth_setup_ip4_fragmentation(const void *l2hdr, size_t
l2hdr_len,
orig_flags = be16_to_cpu(iphdr->ip_off) & ~(IP_OFFMASK|IP_MF);
new_ip_off = frag_off_units | orig_flags | (more_frags ? IP_MF : 0);
iphdr->ip_off = cpu_to_be16(new_ip_off);
- iphdr->ip_len = cpu_to_be16(l3payload_len + l3hdr_len);
+ iphdr->ip_len = cpu_to_be16(l3payload_len + *l3hdr_len);
+
+ eth_fix_ip4_checksum(l3hdr, *l3hdr_len);
+ } else if (l3_proto == ETH_P_IPV6) {
+ struct ip6_header *ip6 = (struct ip6_header *) l3hdr;
+
+ struct ip6_ext_hdr_fragment *frag_ext = NULL;
+
+ /* Find frag extension */
+ frag_ext = eth_ip6_find_ext(ip6, IP6_FRAGMENT);
+ if (frag_ext == NULL) {
+ /* No frag extension? Add one */
+ if (*l3hdr_len + sizeof(*frag_ext) > l3hdr_max_len) {
+ /*
+ * TODO:
+ * For now, qemu's L3 buffer allocated with NetTxPkt
+ * and have enough memory(buffer allocated with 65K bytes
+ * ETH_MAX_IP_DGRAM_LEN = 0xFFFF)
+ * for additional extensions.
+ */
+ return; /* TODO: request to reallocate l3hdr */
+ }
+ frag_ext = eth_ip6_add_ext_nonsafe(ip6, IP6_FRAGMENT);
+ *l3hdr_len += sizeof(*frag_ext);
+ static uint32_t s_id = s_first_fragment_identificator;
+ frag_ext->id = cpu_to_be32(s_id);
+ ++s_id;
+ }
+
+ frag_ext->off = cpu_to_be16((frag_offset / IP_FRAG_UNIT_SIZE) << 3
+ | (uint16_t)!!more_frags);
+
+ ip6->ip6_plen = cpu_to_be16(l3payload_len + *l3hdr_len - sizeof(*ip6));
}
}
--
2.27.0
