===============================
Generic Receive Offload (GRO) is a widely used SW-based offloading
-technique to reduce per-packet processing overhead. It gains performance
-by reassembling small packets into large ones. To enable more flexibility
-to applications, DPDK implements GRO as a standalone library. Applications
-explicitly use the GRO library to merge small packets into large ones.
-
-The GRO library assumes all input packets have correct checksums. In
-addition, the GRO library doesn't re-calculate checksums for merged
-packets. If input packets are IP fragmented, the GRO library assumes
-they are complete packets (i.e. with L4 headers).
-
-Currently, the GRO library implements TCP/IPv4 packet reassembly.
-
-Reassembly Modes
-----------------
-
-The GRO library provides two reassembly modes: lightweight and
-heavyweight mode. If applications want to merge packets in a simple way,
-they can use the lightweight mode API. If applications want more
-fine-grained controls, they can choose the heavyweight mode API.
-
-Lightweight Mode
-~~~~~~~~~~~~~~~~
-
-The ``rte_gro_reassemble_burst()`` function is used for reassembly in
-lightweight mode. It tries to merge N input packets at a time, where
-N should be less than or equal to ``RTE_GRO_MAX_BURST_ITEM_NUM``.
-
-In each invocation, ``rte_gro_reassemble_burst()`` allocates temporary
-reassembly tables for the desired GRO types. Note that the reassembly
-table is a table structure used to reassemble packets and different GRO
-types (e.g. TCP/IPv4 GRO and TCP/IPv6 GRO) have different reassembly table
-structures. The ``rte_gro_reassemble_burst()`` function uses the reassembly
-tables to merge the N input packets.
-
-For applications, performing GRO in lightweight mode is simple. They
-just need to invoke ``rte_gro_reassemble_burst()``. Applications can get
-GROed packets as soon as ``rte_gro_reassemble_burst()`` returns.
-
-Heavyweight Mode
-~~~~~~~~~~~~~~~~
-
-The ``rte_gro_reassemble()`` function is used for reassembly in heavyweight
-mode. Compared with the lightweight mode, performing GRO in heavyweight mode
-is relatively complicated.
-
-Before performing GRO, applications need to create a GRO context object
-by calling ``rte_gro_ctx_create()``. A GRO context object holds the
-reassembly tables of desired GRO types. Note that all update/lookup
-operations on the context object are not thread safe. So if different
-processes or threads want to access the same context object simultaneously,
-some external syncing mechanisms must be used.
-
-Once the GRO context is created, applications can then use the
-``rte_gro_reassemble()`` function to merge packets. In each invocation,
-``rte_gro_reassemble()`` tries to merge input packets with the packets
-in the reassembly tables. If an input packet is an unsupported GRO type,
-or other errors happen (e.g. SYN bit is set), ``rte_gro_reassemble()``
-returns the packet to applications. Otherwise, the input packet is either
-merged or inserted into a reassembly table.
-
-When applications want to get GRO processed packets, they need to use
-``rte_gro_timeout_flush()`` to flush them from the tables manually.
+technique to reduce per-packet processing overheads. By reassembling
+small packets into larger ones, GRO enables applications to process
+fewer large packets directly, thus reducing the number of packets to
+be processed. To benefit DPDK-based applications, like Open vSwitch,
+DPDK also provides own GRO implementation. In DPDK, GRO is implemented
+as a standalone library. Applications explicitly use the GRO library to
+reassemble packets.
+
+Overview
+--------
+
+In the GRO library, there are many GRO types which are defined by packet
+types. One GRO type is in charge of process one kind of packets. For
+example, TCP/IPv4 GRO processes TCP/IPv4 packets.
+
+Each GRO type has a reassembly function, which defines own algorithm and
+table structure to reassemble packets. We assign input packets to the
+corresponding GRO functions by MBUF->packet_type.
+
+The GRO library doesn't check if input packets have correct checksums and
+doesn't re-calculate checksums for merged packets. The GRO library
+assumes the packets are complete (i.e., MF==0 && frag_off==0), when IP
+fragmentation is possible (i.e., DF==0). Additionally, it requires IPv4
+ID to be increased by one.
-TCP/IPv4 GRO
-------------
+Currently, the GRO library provides GRO supports for TCP/IPv4 packets.
+
+Two Sets of API
+---------------
+
+For different usage scenarios, the GRO library provides two sets of API.
+The one is called the lightweight mode API, which enables applications to
+merge a small number of packets rapidly; the other is called the
+heavyweight mode API, which provides fine-grained controls to
+applications and supports to merge a large number of packets.
+
+Lightweight Mode API
+~~~~~~~~~~~~~~~~~~~~
+
+The lightweight mode only has one function ``rte_gro_reassemble_burst()``,
+which process N packets at a time. Using the lightweight mode API to
+merge packets is very simple. Calling ``rte_gro_reassemble_burst()`` is
+enough. The GROed packets are returned to applications as soon as it
+finishes.
+
+In ``rte_gro_reassemble_burst()``, table structures of different GRO
+types are allocated in the stack. This design simplifies applications'
+operations. However, limited by the stack size, the maximum number of
+packets that ``rte_gro_reassemble_burst()`` can process in an invocation
+should be less than or equal to ``RTE_GRO_MAX_BURST_ITEM_NUM``.
+
+Heavyweight Mode API
+~~~~~~~~~~~~~~~~~~~~
+
+Compared with the lightweight mode, using the heavyweight mode API is
+relatively complex. Firstly, applications need to create a GRO context
+by ``rte_gro_ctx_create()``. ``rte_gro_ctx_create()`` allocates tables
+structures in the heap and stores their pointers in the GRO context.
+Secondly, applications use ``rte_gro_reassemble()`` to merge packets.
+If input packets have invalid parameters, ``rte_gro_reassemble()``
+returns them to applications. For example, packets of unsupported GRO
+types or TCP SYN packets are returned. Otherwise, the input packets are
+either merged with the existed packets in the tables or inserted into the
+tables. Finally, applications use ``rte_gro_timeout_flush()`` to flush
+packets from the tables, when they want to get the GROed packets.
+
+Note that all update/lookup operations on the GRO context are not thread
+safe. So if different processes or threads want to access the same
+context object simultaneously, some external syncing mechanisms must be
+used.
+
+Reassembly Algorithm
+--------------------
-TCP/IPv4 GRO supports merging small TCP/IPv4 packets into large ones,
-using a table structure called the TCP/IPv4 reassembly table.
+The reassembly algorithm is used for reassembling packets. In the GRO
+library, different GRO types can use different algorithms. In this
+section, we will introduce an algorithm, which is used by TCP/IPv4 GRO.
-TCP/IPv4 Reassembly Table
-~~~~~~~~~~~~~~~~~~~~~~~~~
+Challenges
+~~~~~~~~~~
-A TCP/IPv4 reassembly table includes a "key" array and an "item" array.
-The key array keeps the criteria to merge packets and the item array
-keeps the packet information.
+The reassembly algorithm determines the efficiency of GRO. There are two
+challenges in the algorithm design:
-Each key in the key array points to an item group, which consists of
-packets which have the same criteria values but can't be merged. A key
-in the key array includes two parts:
+- a high cost algorithm/implementation would cause packet dropping in a
+ high speed network.
-* ``criteria``: the criteria to merge packets. If two packets can be
- merged, they must have the same criteria values.
+- packet reordering makes it hard to merge packets. For example, Linux
+ GRO fails to merge packets when encounters packet reordering.
-* ``start_index``: the item array index of the first packet in the item
- group.
+The above two challenges require our algorithm is:
-Each element in the item array keeps the information of a packet. An item
-in the item array mainly includes three parts:
+- lightweight enough to scale fast networking speed
-* ``firstseg``: the mbuf address of the first segment of the packet.
+- capable of handling packet reordering
-* ``lastseg``: the mbuf address of the last segment of the packet.
+In DPDK GRO, we use a key-based algorithm to address the two challenges.
-* ``next_pkt_index``: the item array index of the next packet in the same
- item group. TCP/IPv4 GRO uses ``next_pkt_index`` to chain the packets
- that have the same criteria value but can't be merged together.
+Key-based Reassembly Algorithm
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+:numref:`figure_gro-key-algorithm` illustrates the procedure of the
+key-based algorithm. Packets are classified into "flows" by some header
+fields (we call them as "key"). To process an input packet, the algorithm
+searches for a matched "flow" (i.e., the same value of key) for the
+packet first, then checks all packets in the "flow" and tries to find a
+"neighbor" for it. If find a "neighbor", merge the two packets together.
+If can't find a "neighbor", store the packet into its "flow". If can't
+find a matched "flow", insert a new "flow" and store the packet into the
+"flow".
+
+.. note::
+ Packets in the same "flow" that can't merge are always caused
+ by packet reordering.
+
+The key-based algorithm has two characters:
+
+- classifying packets into "flows" to accelerate packet aggregation is
+ simple (address challenge 1).
+
+- storing out-of-order packets makes it possible to merge later (address
+ challenge 2).
+
+.. _figure_gro-key-algorithm:
+
+.. figure:: img/gro-key-algorithm.*
+ :align: center
+
+ Key-based Reassembly Algorithm
+
+TCP/IPv4 GRO
+------------
-Procedure to Reassemble a Packet
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The table structure used by TCP/IPv4 GRO contains two arrays: flow array
+and item array. The flow array keeps flow information, and the item array
+keeps packet information.
-To reassemble an incoming packet needs three steps:
+Header fields used to define a TCP/IPv4 flow include:
-#. Check if the packet should be processed. Packets with one of the
- following properties aren't processed and are returned immediately:
+- source and destination: Ethernet and IP address, TCP port
- * FIN, SYN, RST, URG, PSH, ECE or CWR bit is set.
+- TCP acknowledge number
- * L4 payload length is 0.
+TCP/IPv4 packets whose FIN, SYN, RST, URG, PSH, ECE or CWR bit is set
+won't be processed.
-#. Traverse the key array to find a key which has the same criteria
- value with the incoming packet. If found, go to the next step.
- Otherwise, insert a new key and a new item for the packet.
+Header fields deciding if two packets are neighbors include:
-#. Locate the first packet in the item group via ``start_index``. Then
- traverse all packets in the item group via ``next_pkt_index``. If a
- packet is found which can be merged with the incoming one, merge them
- together. If one isn't found, insert the packet into this item group.
- Note that to merge two packets is to link them together via mbuf's
- ``next`` field.
+- TCP sequence number
-When packets are flushed from the reassembly table, TCP/IPv4 GRO updates
-packet header fields for the merged packets. Note that before reassembling
-the packet, TCP/IPv4 GRO doesn't check if the checksums of packets are
-correct. Also, TCP/IPv4 GRO doesn't re-calculate checksums for merged
-packets.
+- IPv4 ID. The IPv4 ID fields of the packets should be increased by 1.
--- /dev/null
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+ <text x="6.41" y="186.88" class="st9" v:langID="1033"><v:paragraph v:horizAlign="1"/><v:tabList/>find a “flow”</text> </g>
+ <g id="shape15-69" v:mID="15" v:groupContext="shape" transform="translate(99.25,-39.625)">
+ <title>Sheet.15</title>
+ <desc>find a “neighbor”</desc>
+ <v:userDefs>
+ <v:ud v:nameU="msvThemeColors" v:val="VT0(36):26"/>
+ <v:ud v:nameU="msvThemeEffects" v:val="VT0(16):26"/>
+ </v:userDefs>
+ <v:textBlock v:margins="rect(4,4,4,4)"/>
+ <v:textRect cx="40.5" cy="183.875" width="81" height="15.75"/>
+ <rect x="0" y="176" width="81" height="15.75" class="st8"/>
+ <text x="5.48" y="186.88" class="st9" v:langID="1033"><v:paragraph v:horizAlign="1"/><v:tabList/>find a “neighbor”</text> </g>
+ <g id="shape13-72" v:mID="13" v:groupContext="shape" transform="translate(181.375,-79)">
+ <title>Sheet.13</title>
+ <desc>not find</desc>
+ <v:userDefs>
+ <v:ud v:nameU="msvThemeColors" v:val="VT0(36):26"/>
+ <v:ud v:nameU="msvThemeEffects" v:val="VT0(16):26"/>
+ </v:userDefs>
+ <v:textBlock v:margins="rect(4,4,4,4)"/>
+ <v:textRect cx="21.375" cy="183.875" width="42.75" height="15.75"/>
+ <rect x="0" y="176" width="42.75" height="15.75" class="st8"/>
+ <text x="5.38" y="186.88" class="st9" v:langID="1033"><v:paragraph v:horizAlign="1"/><v:tabList/>not find</text> </g>
+ <g id="shape12-75" v:mID="12" v:groupContext="shape" transform="translate(181.375,-137.5)">
+ <title>Sheet.12</title>
+ <desc>not find</desc>
+ <v:userDefs>
+ <v:ud v:nameU="msvThemeColors" v:val="VT0(36):26"/>
+ <v:ud v:nameU="msvThemeEffects" v:val="VT0(16):26"/>
+ </v:userDefs>
+ <v:textBlock v:margins="rect(4,4,4,4)"/>
+ <v:textRect cx="21.375" cy="183.875" width="42.75" height="15.75"/>
+ <rect x="0" y="176" width="42.75" height="15.75" class="st8"/>
+ <text x="5.38" y="186.88" class="st9" v:langID="1033"><v:paragraph v:horizAlign="1"/><v:tabList/>not find</text> </g>
+ </g>
+</svg>
}
tbl->max_item_num = entries_num;
- size = sizeof(struct gro_tcp4_key) * entries_num;
- tbl->keys = rte_zmalloc_socket(__func__,
+ size = sizeof(struct gro_tcp4_flow) * entries_num;
+ tbl->flows = rte_zmalloc_socket(__func__,
size,
RTE_CACHE_LINE_SIZE,
socket_id);
- if (tbl->keys == NULL) {
+ if (tbl->flows == NULL) {
rte_free(tbl->items);
rte_free(tbl);
return NULL;
}
- /* INVALID_ARRAY_INDEX indicates empty key */
+ /* INVALID_ARRAY_INDEX indicates an empty flow */
for (i = 0; i < entries_num; i++)
- tbl->keys[i].start_index = INVALID_ARRAY_INDEX;
- tbl->max_key_num = entries_num;
+ tbl->flows[i].start_index = INVALID_ARRAY_INDEX;
+ tbl->max_flow_num = entries_num;
return tbl;
}
if (tcp_tbl) {
rte_free(tcp_tbl->items);
- rte_free(tcp_tbl->keys);
+ rte_free(tcp_tbl->flows);
}
rte_free(tcp_tbl);
}
* the original packet.
*/
static inline int
-merge_two_tcp4_packets(struct gro_tcp4_item *item_src,
+merge_two_tcp4_packets(struct gro_tcp4_item *item,
struct rte_mbuf *pkt,
- uint16_t ip_id,
+ int cmp,
uint32_t sent_seq,
- int cmp)
+ uint16_t ip_id)
{
struct rte_mbuf *pkt_head, *pkt_tail, *lastseg;
- uint16_t tcp_datalen;
+ uint16_t hdr_len;
if (cmp > 0) {
- pkt_head = item_src->firstseg;
+ pkt_head = item->firstseg;
pkt_tail = pkt;
} else {
pkt_head = pkt;
- pkt_tail = item_src->firstseg;
+ pkt_tail = item->firstseg;
}
- /* check if the packet length will be beyond the max value */
- tcp_datalen = pkt_tail->pkt_len - pkt_tail->l2_len -
- pkt_tail->l3_len - pkt_tail->l4_len;
- if (pkt_head->pkt_len - pkt_head->l2_len + tcp_datalen >
- TCP4_MAX_L3_LENGTH)
+ /* check if the IPv4 packet length is greater than the max value */
+ hdr_len = pkt_head->l2_len + pkt_head->l3_len + pkt_head->l4_len;
+ if (unlikely(pkt_head->pkt_len - pkt_head->l2_len + pkt_tail->pkt_len -
+ hdr_len > MAX_IPV4_PKT_LENGTH))
return 0;
- /* remove packet header for the tail packet */
- rte_pktmbuf_adj(pkt_tail,
- pkt_tail->l2_len +
- pkt_tail->l3_len +
- pkt_tail->l4_len);
+ /* remove the packet header for the tail packet */
+ rte_pktmbuf_adj(pkt_tail, hdr_len);
/* chain two packets together */
if (cmp > 0) {
- item_src->lastseg->next = pkt;
- item_src->lastseg = rte_pktmbuf_lastseg(pkt);
+ item->lastseg->next = pkt;
+ item->lastseg = rte_pktmbuf_lastseg(pkt);
/* update IP ID to the larger value */
- item_src->ip_id = ip_id;
+ item->ip_id = ip_id;
} else {
lastseg = rte_pktmbuf_lastseg(pkt);
- lastseg->next = item_src->firstseg;
- item_src->firstseg = pkt;
+ lastseg->next = item->firstseg;
+ item->firstseg = pkt;
/* update sent_seq to the smaller value */
- item_src->sent_seq = sent_seq;
+ item->sent_seq = sent_seq;
}
- item_src->nb_merged++;
+ item->nb_merged++;
/* update mbuf metadata for the merged packet */
pkt_head->nb_segs += pkt_tail->nb_segs;
return 1;
}
+/*
+ * Check if two TCP/IPv4 packets are neighbors.
+ */
static inline int
check_seq_option(struct gro_tcp4_item *item,
- struct tcp_hdr *tcp_hdr,
- uint16_t tcp_hl,
- uint16_t tcp_dl,
+ struct tcp_hdr *tcph,
+ uint32_t sent_seq,
uint16_t ip_id,
- uint32_t sent_seq)
+ uint16_t tcp_hl,
+ uint16_t tcp_dl)
{
- struct rte_mbuf *pkt0 = item->firstseg;
- struct ipv4_hdr *ipv4_hdr0;
- struct tcp_hdr *tcp_hdr0;
- uint16_t tcp_hl0, tcp_dl0;
- uint16_t len;
-
- ipv4_hdr0 = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt0, char *) +
- pkt0->l2_len);
- tcp_hdr0 = (struct tcp_hdr *)((char *)ipv4_hdr0 + pkt0->l3_len);
- tcp_hl0 = pkt0->l4_len;
-
- /* check if TCP option fields equal. If not, return 0. */
- len = RTE_MAX(tcp_hl, tcp_hl0) - sizeof(struct tcp_hdr);
- if ((tcp_hl != tcp_hl0) ||
- ((len > 0) && (memcmp(tcp_hdr + 1,
- tcp_hdr0 + 1,
+ struct rte_mbuf *pkt_orig = item->firstseg;
+ struct ipv4_hdr *iph_orig;
+ struct tcp_hdr *tcph_orig;
+ uint16_t len, tcp_hl_orig;
+
+ iph_orig = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt_orig, char *) +
+ pkt_orig->l2_len);
+ tcph_orig = (struct tcp_hdr *)((char *)iph_orig + pkt_orig->l3_len);
+ tcp_hl_orig = pkt_orig->l4_len;
+
+ /* Check if TCP option fields equal */
+ len = RTE_MAX(tcp_hl, tcp_hl_orig) - sizeof(struct tcp_hdr);
+ if ((tcp_hl != tcp_hl_orig) ||
+ ((len > 0) && (memcmp(tcph + 1, tcph_orig + 1,
len) != 0)))
return 0;
/* check if the two packets are neighbors */
- tcp_dl0 = pkt0->pkt_len - pkt0->l2_len - pkt0->l3_len - tcp_hl0;
- if ((sent_seq == (item->sent_seq + tcp_dl0)) &&
- (ip_id == (item->ip_id + 1)))
+ len = pkt_orig->pkt_len - pkt_orig->l2_len - pkt_orig->l3_len -
+ tcp_hl_orig;
+ if ((sent_seq == item->sent_seq + len) && (ip_id == item->ip_id + 1))
/* append the new packet */
return 1;
- else if (((sent_seq + tcp_dl) == item->sent_seq) &&
- ((ip_id + item->nb_merged) == item->ip_id))
+ else if ((sent_seq + tcp_dl == item->sent_seq) &&
+ (ip_id + item->nb_merged == item->ip_id))
/* pre-pend the new packet */
return -1;
- else
- return 0;
+
+ return 0;
}
static inline uint32_t
}
static inline uint32_t
-find_an_empty_key(struct gro_tcp4_tbl *tbl)
+find_an_empty_flow(struct gro_tcp4_tbl *tbl)
{
uint32_t i;
- uint32_t max_key_num = tbl->max_key_num;
+ uint32_t max_flow_num = tbl->max_flow_num;
- for (i = 0; i < max_key_num; i++)
- if (tbl->keys[i].start_index == INVALID_ARRAY_INDEX)
+ for (i = 0; i < max_flow_num; i++)
+ if (tbl->flows[i].start_index == INVALID_ARRAY_INDEX)
return i;
return INVALID_ARRAY_INDEX;
}
static inline uint32_t
insert_new_item(struct gro_tcp4_tbl *tbl,
struct rte_mbuf *pkt,
- uint16_t ip_id,
- uint32_t sent_seq,
+ uint64_t start_time,
uint32_t prev_idx,
- uint64_t start_time)
+ uint32_t sent_seq,
+ uint16_t ip_id)
{
uint32_t item_idx;
tbl->items[item_idx].nb_merged = 1;
tbl->item_num++;
- /* if the previous packet exists, chain the new one with it */
+ /* if the previous packet exists, chain them together. */
if (prev_idx != INVALID_ARRAY_INDEX) {
tbl->items[item_idx].next_pkt_idx =
tbl->items[prev_idx].next_pkt_idx;
{
uint32_t next_idx = tbl->items[item_idx].next_pkt_idx;
- /* set NULL to firstseg to indicate it's an empty item */
+ /* NULL indicates an empty item */
tbl->items[item_idx].firstseg = NULL;
tbl->item_num--;
if (prev_item_idx != INVALID_ARRAY_INDEX)
}
static inline uint32_t
-insert_new_key(struct gro_tcp4_tbl *tbl,
- struct tcp4_key *key_src,
+insert_new_flow(struct gro_tcp4_tbl *tbl,
+ struct tcp4_flow_key *src,
uint32_t item_idx)
{
- struct tcp4_key *key_dst;
- uint32_t key_idx;
+ struct tcp4_flow_key *dst;
+ uint32_t flow_idx;
- key_idx = find_an_empty_key(tbl);
- if (key_idx == INVALID_ARRAY_INDEX)
+ flow_idx = find_an_empty_flow(tbl);
+ if (unlikely(flow_idx == INVALID_ARRAY_INDEX))
return INVALID_ARRAY_INDEX;
- key_dst = &(tbl->keys[key_idx].key);
+ dst = &(tbl->flows[flow_idx].key);
- ether_addr_copy(&(key_src->eth_saddr), &(key_dst->eth_saddr));
- ether_addr_copy(&(key_src->eth_daddr), &(key_dst->eth_daddr));
- key_dst->ip_src_addr = key_src->ip_src_addr;
- key_dst->ip_dst_addr = key_src->ip_dst_addr;
- key_dst->recv_ack = key_src->recv_ack;
- key_dst->src_port = key_src->src_port;
- key_dst->dst_port = key_src->dst_port;
+ ether_addr_copy(&(src->eth_saddr), &(dst->eth_saddr));
+ ether_addr_copy(&(src->eth_daddr), &(dst->eth_daddr));
+ dst->ip_src_addr = src->ip_src_addr;
+ dst->ip_dst_addr = src->ip_dst_addr;
+ dst->recv_ack = src->recv_ack;
+ dst->src_port = src->src_port;
+ dst->dst_port = src->dst_port;
- /* non-INVALID_ARRAY_INDEX value indicates this key is valid */
- tbl->keys[key_idx].start_index = item_idx;
- tbl->key_num++;
+ tbl->flows[flow_idx].start_index = item_idx;
+ tbl->flow_num++;
- return key_idx;
+ return flow_idx;
}
+/*
+ * Check if two TCP/IPv4 packets belong to the same flow.
+ */
static inline int
-is_same_key(struct tcp4_key k1, struct tcp4_key k2)
+is_same_tcp4_flow(struct tcp4_flow_key k1, struct tcp4_flow_key k2)
{
- if (is_same_ether_addr(&k1.eth_saddr, &k2.eth_saddr) == 0)
- return 0;
-
- if (is_same_ether_addr(&k1.eth_daddr, &k2.eth_daddr) == 0)
- return 0;
-
- return ((k1.ip_src_addr == k2.ip_src_addr) &&
+ return (is_same_ether_addr(&k1.eth_saddr, &k2.eth_saddr) &&
+ is_same_ether_addr(&k1.eth_daddr, &k2.eth_daddr) &&
+ (k1.ip_src_addr == k2.ip_src_addr) &&
(k1.ip_dst_addr == k2.ip_dst_addr) &&
(k1.recv_ack == k2.recv_ack) &&
(k1.src_port == k2.src_port) &&
}
/*
- * update packet length for the flushed packet.
+ * update the packet length for the flushed packet.
*/
static inline void
update_header(struct gro_tcp4_item *item)
struct ipv4_hdr *ipv4_hdr;
struct tcp_hdr *tcp_hdr;
uint32_t sent_seq;
- uint16_t tcp_dl, ip_id;
+ uint16_t tcp_dl, ip_id, hdr_len;
- struct tcp4_key key;
+ struct tcp4_flow_key key;
uint32_t cur_idx, prev_idx, item_idx;
- uint32_t i, max_key_num;
+ uint32_t i, max_flow_num, remaining_flow_num;
int cmp;
+ uint8_t find;
eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
ipv4_hdr = (struct ipv4_hdr *)((char *)eth_hdr + pkt->l2_len);
tcp_hdr = (struct tcp_hdr *)((char *)ipv4_hdr + pkt->l3_len);
+ hdr_len = pkt->l2_len + pkt->l3_len + pkt->l4_len;
/*
- * if FIN, SYN, RST, PSH, URG, ECE or
- * CWR is set, return immediately.
+ * Don't process the packet which has FIN, SYN, RST, PSH, URG, ECE
+ * or CWR set.
*/
if (tcp_hdr->tcp_flags != TCP_ACK_FLAG)
return -1;
- /* if payload length is 0, return immediately */
- tcp_dl = rte_be_to_cpu_16(ipv4_hdr->total_length) - pkt->l3_len -
- pkt->l4_len;
- if (tcp_dl == 0)
+ /*
+ * Don't process the packet whose payload length is less than or
+ * equal to 0.
+ */
+ tcp_dl = pkt->pkt_len - hdr_len;
+ if (tcp_dl <= 0)
return -1;
ip_id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
key.dst_port = tcp_hdr->dst_port;
key.recv_ack = tcp_hdr->recv_ack;
- /* search for a key */
- max_key_num = tbl->max_key_num;
- for (i = 0; i < max_key_num; i++) {
- if ((tbl->keys[i].start_index != INVALID_ARRAY_INDEX) &&
- is_same_key(tbl->keys[i].key, key))
- break;
+ /* Search for a matched flow. */
+ max_flow_num = tbl->max_flow_num;
+ remaining_flow_num = tbl->flow_num;
+ find = 0;
+ for (i = 0; i < max_flow_num && remaining_flow_num; i++) {
+ if (tbl->flows[i].start_index != INVALID_ARRAY_INDEX) {
+ if (is_same_tcp4_flow(tbl->flows[i].key, key)) {
+ find = 1;
+ break;
+ }
+ remaining_flow_num--;
+ }
}
- /* can't find a key, so insert a new key and a new item. */
- if (i == tbl->max_key_num) {
- item_idx = insert_new_item(tbl, pkt, ip_id, sent_seq,
- INVALID_ARRAY_INDEX, start_time);
+ /*
+ * Fail to find a matched flow. Insert a new flow and store the
+ * packet into the flow.
+ */
+ if (find == 0) {
+ item_idx = insert_new_item(tbl, pkt, start_time,
+ INVALID_ARRAY_INDEX, sent_seq, ip_id);
if (item_idx == INVALID_ARRAY_INDEX)
return -1;
- if (insert_new_key(tbl, &key, item_idx) ==
+ if (insert_new_flow(tbl, &key, item_idx) ==
INVALID_ARRAY_INDEX) {
/*
- * fail to insert a new key, so
- * delete the inserted item
+ * Fail to insert a new flow, so delete the
+ * stored packet.
*/
delete_item(tbl, item_idx, INVALID_ARRAY_INDEX);
return -1;
return 0;
}
- /* traverse all packets in the item group to find one to merge */
- cur_idx = tbl->keys[i].start_index;
+ /*
+ * Check all packets in the flow and try to find a neighbor for
+ * the input packet.
+ */
+ cur_idx = tbl->flows[i].start_index;
prev_idx = cur_idx;
do {
cmp = check_seq_option(&(tbl->items[cur_idx]), tcp_hdr,
- pkt->l4_len, tcp_dl, ip_id, sent_seq);
+ sent_seq, ip_id, pkt->l4_len, tcp_dl);
if (cmp) {
if (merge_two_tcp4_packets(&(tbl->items[cur_idx]),
- pkt, ip_id,
- sent_seq, cmp))
+ pkt, cmp, sent_seq, ip_id))
return 1;
/*
- * fail to merge two packets since the packet
- * length will be greater than the max value.
- * So insert the packet into the item group.
+ * Fail to merge the two packets, as the packet
+ * length is greater than the max value. Store
+ * the packet into the flow.
*/
- if (insert_new_item(tbl, pkt, ip_id, sent_seq,
- prev_idx, start_time) ==
+ if (insert_new_item(tbl, pkt, start_time, prev_idx,
+ sent_seq, ip_id) ==
INVALID_ARRAY_INDEX)
return -1;
return 0;
cur_idx = tbl->items[cur_idx].next_pkt_idx;
} while (cur_idx != INVALID_ARRAY_INDEX);
- /*
- * can't find a packet in the item group to merge,
- * so insert the packet into the item group.
- */
- if (insert_new_item(tbl, pkt, ip_id, sent_seq, prev_idx,
- start_time) == INVALID_ARRAY_INDEX)
+ /* Fail to find a neighbor, so store the packet into the flow. */
+ if (insert_new_item(tbl, pkt, start_time, prev_idx, sent_seq,
+ ip_id) == INVALID_ARRAY_INDEX)
return -1;
return 0;
{
uint16_t k = 0;
uint32_t i, j;
- uint32_t max_key_num = tbl->max_key_num;
+ uint32_t max_flow_num = tbl->max_flow_num;
- for (i = 0; i < max_key_num; i++) {
- /* all keys have been checked, return immediately */
- if (tbl->key_num == 0)
+ for (i = 0; i < max_flow_num; i++) {
+ if (unlikely(tbl->flow_num == 0))
return k;
- j = tbl->keys[i].start_index;
+ j = tbl->flows[i].start_index;
while (j != INVALID_ARRAY_INDEX) {
if (tbl->items[j].start_time <= flush_timestamp) {
out[k++] = tbl->items[j].firstseg;
if (tbl->items[j].nb_merged > 1)
update_header(&(tbl->items[j]));
/*
- * delete the item and get
- * the next packet index
+ * Delete the packet and get the next
+ * packet in the flow.
*/
- j = delete_item(tbl, j,
- INVALID_ARRAY_INDEX);
+ j = delete_item(tbl, j, INVALID_ARRAY_INDEX);
+ tbl->flows[i].start_index = j;
+ if (j == INVALID_ARRAY_INDEX)
+ tbl->flow_num--;
- /*
- * delete the key as all of
- * packets are flushed
- */
- if (j == INVALID_ARRAY_INDEX) {
- tbl->keys[i].start_index =
- INVALID_ARRAY_INDEX;
- tbl->key_num--;
- } else
- /* update start_index of the key */
- tbl->keys[i].start_index = j;
-
- if (k == nb_out)
+ if (unlikely(k == nb_out))
return k;
} else
/*
- * left packets of this key won't be
- * timeout, so go to check other keys.
+ * The left packets in this flow won't be
+ * timeout. Go to check other flows.
*/
break;
}
#define GRO_TCP4_TBL_MAX_ITEM_NUM (1024UL * 1024UL)
/*
- * the max L3 length of a TCP/IPv4 packet. The L3 length
- * is the sum of ipv4 header, tcp header and L4 payload.
+ * The max length of a IPv4 packet, which includes the length of the L3
+ * header, the L4 header and the data payload.
*/
-#define TCP4_MAX_L3_LENGTH UINT16_MAX
+#define MAX_IPV4_PKT_LENGTH UINT16_MAX
-/* criteria of mergeing packets */
-struct tcp4_key {
+/* Header fields representing a TCP/IPv4 flow */
+struct tcp4_flow_key {
struct ether_addr eth_saddr;
struct ether_addr eth_daddr;
uint32_t ip_src_addr;
uint16_t dst_port;
};
-struct gro_tcp4_key {
- struct tcp4_key key;
+struct gro_tcp4_flow {
+ struct tcp4_flow_key key;
/*
- * the index of the first packet in the item group.
- * If the value is INVALID_ARRAY_INDEX, it means
- * the key is empty.
+ * The index of the first packet in the flow.
+ * INVALID_ARRAY_INDEX indicates an empty flow.
*/
uint32_t start_index;
};
struct gro_tcp4_item {
/*
- * first segment of the packet. If the value
+ * The first MBUF segment of the packet. If the value
* is NULL, it means the item is empty.
*/
struct rte_mbuf *firstseg;
- /* last segment of the packet */
+ /* The last MBUF segment of the packet */
struct rte_mbuf *lastseg;
/*
- * the time when the first packet is inserted
- * into the table. If a packet in the table is
- * merged with an incoming packet, this value
- * won't be updated. We set this value only
- * when the first packet is inserted into the
- * table.
+ * The time when the first packet is inserted into the table.
+ * This value won't be updated, even if the packet is merged
+ * with other packets.
*/
uint64_t start_time;
/*
- * we use next_pkt_idx to chain the packets that
- * have same key value but can't be merged together.
+ * next_pkt_idx is used to chain the packets that
+ * are in the same flow but can't be merged together
+ * (e.g. caused by packet reordering).
*/
uint32_t next_pkt_idx;
- /* the sequence number of the packet */
+ /* TCP sequence number of the packet */
uint32_t sent_seq;
- /* the IP ID of the packet */
+ /* IPv4 ID of the packet */
uint16_t ip_id;
/* the number of merged packets */
uint16_t nb_merged;
struct gro_tcp4_tbl {
/* item array */
struct gro_tcp4_item *items;
- /* key array */
- struct gro_tcp4_key *keys;
+ /* flow array */
+ struct gro_tcp4_flow *flows;
/* current item number */
uint32_t item_num;
- /* current key num */
- uint32_t key_num;
+ /* current flow num */
+ uint32_t flow_num;
/* item array size */
uint32_t max_item_num;
- /* key array size */
- uint32_t max_key_num;
+ /* flow array size */
+ uint32_t max_flow_num;
};
/**
* This function creates a TCP/IPv4 reassembly table.
*
* @param socket_id
- * socket index for allocating TCP/IPv4 reassemble table
+ * Socket index for allocating the TCP/IPv4 reassemble table
* @param max_flow_num
- * the maximum number of flows in the TCP/IPv4 GRO table
+ * The maximum number of flows in the TCP/IPv4 GRO table
* @param max_item_per_flow
- * the maximum packet number per flow.
+ * The maximum number of packets per flow
*
* @return
- * if create successfully, return a pointer which points to the
- * created TCP/IPv4 GRO table. Otherwise, return NULL.
+ * - Return the table pointer on success.
+ * - Return NULL on failure.
*/
void *gro_tcp4_tbl_create(uint16_t socket_id,
uint16_t max_flow_num,
* This function destroys a TCP/IPv4 reassembly table.
*
* @param tbl
- * a pointer points to the TCP/IPv4 reassembly table.
+ * Pointer pointing to the TCP/IPv4 reassembly table.
*/
void gro_tcp4_tbl_destroy(void *tbl);
/**
- * This function searches for a packet in the TCP/IPv4 reassembly table
- * to merge with the inputted one. To merge two packets is to chain them
- * together and update packet headers. Packets, whose SYN, FIN, RST, PSH
- * CWR, ECE or URG bit is set, are returned immediately. Packets which
- * only have packet headers (i.e. without data) are also returned
- * immediately. Otherwise, the packet is either merged, or inserted into
- * the table. Besides, if there is no available space to insert the
- * packet, this function returns immediately too.
+ * This function merges a TCP/IPv4 packet. It doesn't process the packet,
+ * which has SYN, FIN, RST, PSH, CWR, ECE or URG set, or doesn't have
+ * payload.
*
- * This function assumes the inputted packet is with correct IPv4 and
- * TCP checksums. And if two packets are merged, it won't re-calculate
- * IPv4 and TCP checksums. Besides, if the inputted packet is IP
- * fragmented, it assumes the packet is complete (with TCP header).
+ * This function doesn't check if the packet has correct checksums and
+ * doesn't re-calculate checksums for the merged packet. Additionally,
+ * it assumes the packets are complete (i.e., MF==0 && frag_off==0),
+ * when IP fragmentation is possible (i.e., DF==0). It returns the
+ * packet, if the packet has invalid parameters (e.g. SYN bit is set)
+ * or there is no available space in the table.
*
* @param pkt
- * packet to reassemble.
+ * Packet to reassemble
* @param tbl
- * a pointer that points to a TCP/IPv4 reassembly table.
+ * Pointer pointing to the TCP/IPv4 reassembly table
* @start_time
- * the start time that the packet is inserted into the table
+ * The time when the packet is inserted into the table
*
* @return
- * if the packet doesn't have data, or SYN, FIN, RST, PSH, CWR, ECE
- * or URG bit is set, or there is no available space in the table to
- * insert a new item or a new key, return a negative value. If the
- * packet is merged successfully, return an positive value. If the
- * packet is inserted into the table, return 0.
+ * - Return a positive value if the packet is merged.
+ * - Return zero if the packet isn't merged but stored in the table.
+ * - Return a negative value for invalid parameters or no available
+ * space in the table.
*/
int32_t gro_tcp4_reassemble(struct rte_mbuf *pkt,
struct gro_tcp4_tbl *tbl,
uint64_t start_time);
/**
- * This function flushes timeout packets in a TCP/IPv4 reassembly table
- * to applications, and without updating checksums for merged packets.
- * The max number of flushed timeout packets is the element number of
- * the array which is used to keep flushed packets.
+ * This function flushes timeout packets in a TCP/IPv4 reassembly table,
+ * and without updating checksums.
*
* @param tbl
- * a pointer that points to a TCP GRO table.
+ * TCP/IPv4 reassembly table pointer
* @param flush_timestamp
- * this function flushes packets which are inserted into the table
- * before or at the flush_timestamp.
+ * Flush packets which are inserted into the table before or at the
+ * flush_timestamp.
* @param out
- * pointer array which is used to keep flushed packets.
+ * Pointer array used to keep flushed packets
* @param nb_out
- * the element number of out. It's also the max number of timeout
+ * The element number in 'out'. It also determines the maximum number of
* packets that can be flushed finally.
*
* @return
- * the number of packets that are returned.
+ * The number of flushed packets
*/
uint16_t gro_tcp4_tbl_timeout_flush(struct gro_tcp4_tbl *tbl,
uint64_t flush_timestamp,
* reassembly table.
*
* @param tbl
- * pointer points to a TCP/IPv4 reassembly table.
+ * TCP/IPv4 reassembly table pointer
*
* @return
- * the number of packets in the table
+ * The number of packets in the table
*/
uint32_t gro_tcp4_tbl_pkt_count(void *tbl);
#endif
static gro_tbl_pkt_count_fn tbl_pkt_count_fn[RTE_GRO_TYPE_MAX_NUM] = {
gro_tcp4_tbl_pkt_count, NULL};
+#define IS_IPV4_TCP_PKT(ptype) (RTE_ETH_IS_IPV4_HDR(ptype) && \
+ ((ptype & RTE_PTYPE_L4_TCP) == RTE_PTYPE_L4_TCP))
+
/*
- * GRO context structure, which is used to merge packets. It keeps
- * many reassembly tables of desired GRO types. Applications need to
- * create GRO context objects before using rte_gro_reassemble to
- * perform GRO.
+ * GRO context structure. It keeps the table structures, which are
+ * used to merge packets, for different GRO types. Before using
+ * rte_gro_reassemble(), applications need to create the GRO context
+ * first.
*/
struct gro_ctx {
/* GRO types to perform */
uint64_t gro_type_flag;
uint8_t i;
- if (gro_ctx == NULL)
- return;
for (i = 0; i < RTE_GRO_TYPE_MAX_NUM; i++) {
gro_type_flag = 1ULL << i;
if ((gro_ctx->gro_types & gro_type_flag) == 0)
uint16_t nb_pkts,
const struct rte_gro_param *param)
{
- uint16_t i;
- uint16_t nb_after_gro = nb_pkts;
- uint32_t item_num;
-
/* allocate a reassembly table for TCP/IPv4 GRO */
struct gro_tcp4_tbl tcp_tbl;
- struct gro_tcp4_key tcp_keys[RTE_GRO_MAX_BURST_ITEM_NUM];
+ struct gro_tcp4_flow tcp_flows[RTE_GRO_MAX_BURST_ITEM_NUM];
struct gro_tcp4_item tcp_items[RTE_GRO_MAX_BURST_ITEM_NUM] = {{0} };
struct rte_mbuf *unprocess_pkts[nb_pkts];
- uint16_t unprocess_num = 0;
+ uint32_t item_num;
int32_t ret;
- uint64_t current_time;
+ uint16_t i, unprocess_num = 0, nb_after_gro = nb_pkts;
- if ((param->gro_types & RTE_GRO_TCP_IPV4) == 0)
+ if (unlikely((param->gro_types & RTE_GRO_TCP_IPV4) == 0))
return nb_pkts;
- /* get the actual number of packets */
+ /* Get the maximum number of packets */
item_num = RTE_MIN(nb_pkts, (param->max_flow_num *
- param->max_item_per_flow));
+ param->max_item_per_flow));
item_num = RTE_MIN(item_num, RTE_GRO_MAX_BURST_ITEM_NUM);
for (i = 0; i < item_num; i++)
- tcp_keys[i].start_index = INVALID_ARRAY_INDEX;
+ tcp_flows[i].start_index = INVALID_ARRAY_INDEX;
- tcp_tbl.keys = tcp_keys;
+ tcp_tbl.flows = tcp_flows;
tcp_tbl.items = tcp_items;
- tcp_tbl.key_num = 0;
+ tcp_tbl.flow_num = 0;
tcp_tbl.item_num = 0;
- tcp_tbl.max_key_num = item_num;
+ tcp_tbl.max_flow_num = item_num;
tcp_tbl.max_item_num = item_num;
- current_time = rte_rdtsc();
-
for (i = 0; i < nb_pkts; i++) {
- if ((pkts[i]->packet_type & (RTE_PTYPE_L3_IPV4 |
- RTE_PTYPE_L4_TCP)) ==
- (RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L4_TCP)) {
- ret = gro_tcp4_reassemble(pkts[i],
- &tcp_tbl,
- current_time);
+ if (IS_IPV4_TCP_PKT(pkts[i]->packet_type)) {
+ /*
+ * The timestamp is ignored, since all packets
+ * will be flushed from the tables.
+ */
+ ret = gro_tcp4_reassemble(pkts[i], &tcp_tbl, 0);
if (ret > 0)
/* merge successfully */
nb_after_gro--;
- else if (ret < 0) {
- unprocess_pkts[unprocess_num++] =
- pkts[i];
- }
+ else if (ret < 0)
+ unprocess_pkts[unprocess_num++] = pkts[i];
} else
unprocess_pkts[unprocess_num++] = pkts[i];
}
- /* re-arrange GROed packets */
if (nb_after_gro < nb_pkts) {
- i = gro_tcp4_tbl_timeout_flush(&tcp_tbl, current_time,
- pkts, nb_pkts);
+ /* Flush all packets from the tables */
+ i = gro_tcp4_tbl_timeout_flush(&tcp_tbl, 0, pkts, nb_pkts);
+ /* Copy unprocessed packets */
if (unprocess_num > 0) {
memcpy(&pkts[i], unprocess_pkts,
sizeof(struct rte_mbuf *) *
uint16_t nb_pkts,
void *ctx)
{
- uint16_t i, unprocess_num = 0;
struct rte_mbuf *unprocess_pkts[nb_pkts];
struct gro_ctx *gro_ctx = ctx;
+ void *tcp_tbl;
uint64_t current_time;
+ uint16_t i, unprocess_num = 0;
- if ((gro_ctx->gro_types & RTE_GRO_TCP_IPV4) == 0)
+ if (unlikely((gro_ctx->gro_types & RTE_GRO_TCP_IPV4) == 0))
return nb_pkts;
+ tcp_tbl = gro_ctx->tbls[RTE_GRO_TCP_IPV4_INDEX];
current_time = rte_rdtsc();
for (i = 0; i < nb_pkts; i++) {
- if ((pkts[i]->packet_type & (RTE_PTYPE_L3_IPV4 |
- RTE_PTYPE_L4_TCP)) ==
- (RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L4_TCP)) {
- if (gro_tcp4_reassemble(pkts[i],
- gro_ctx->tbls
- [RTE_GRO_TCP_IPV4_INDEX],
+ if (IS_IPV4_TCP_PKT(pkts[i]->packet_type)) {
+ if (gro_tcp4_reassemble(pkts[i], tcp_tbl,
current_time) < 0)
unprocess_pkts[unprocess_num++] = pkts[i];
} else
unprocess_pkts[unprocess_num++] = pkts[i];
}
if (unprocess_num > 0) {
- memcpy(pkts, unprocess_pkts,
- sizeof(struct rte_mbuf *) *
+ memcpy(pkts, unprocess_pkts, sizeof(struct rte_mbuf *) *
unprocess_num);
}
flush_timestamp,
out, max_nb_out);
}
+
return 0;
}
{
struct gro_ctx *gro_ctx = ctx;
gro_tbl_pkt_count_fn pkt_count_fn;
+ uint64_t gro_types = gro_ctx->gro_types, flag;
uint64_t item_num = 0;
- uint64_t gro_type_flag;
uint8_t i;
- for (i = 0; i < RTE_GRO_TYPE_MAX_NUM; i++) {
- gro_type_flag = 1ULL << i;
- if ((gro_ctx->gro_types & gro_type_flag) == 0)
+ for (i = 0; i < RTE_GRO_TYPE_MAX_NUM && gro_types; i++) {
+ flag = 1ULL << i;
+ if ((gro_types & flag) == 0)
continue;
+ gro_types ^= flag;
pkt_count_fn = tbl_pkt_count_fn[i];
- if (pkt_count_fn == NULL)
- continue;
- item_num += pkt_count_fn(gro_ctx->tbls[i]);
+ if (pkt_count_fn)
+ item_num += pkt_count_fn(gro_ctx->tbls[i]);
}
+
return item_num;
}
/**< TCP/IPv4 GRO flag */
/**
- * A structure which is used to create GRO context objects or tell
- * rte_gro_reassemble_burst() what reassembly rules are demanded.
+ * Structure used to create GRO context objects or used to pass
+ * application-determined parameters to rte_gro_reassemble_burst().
*/
struct rte_gro_param {
uint64_t gro_types;
/**
* This is one of the main reassembly APIs, which merges numbers of
- * packets at a time. It assumes that all inputted packets are with
- * correct checksums. That is, applications should guarantee all
- * inputted packets are correct. Besides, it doesn't re-calculate
- * checksums for merged packets. If inputted packets are IP fragmented,
- * this function assumes them are complete (i.e. with L4 header). After
- * finishing processing, it returns all GROed packets to applications
- * immediately.
+ * packets at a time. It doesn't check if input packets have correct
+ * checksums and doesn't re-calculate checksums for merged packets.
+ * It assumes the packets are complete (i.e., MF==0 && frag_off==0),
+ * when IP fragmentation is possible (i.e., DF==0). The GROed packets
+ * are returned as soon as the function finishes.
*
* @param pkts
- * a pointer array which points to the packets to reassemble. Besides,
- * it keeps mbuf addresses for the GROed packets.
+ * Pointer array pointing to the packets to reassemble. Besides, it
+ * keeps MBUF addresses for the GROed packets.
* @param nb_pkts
- * the number of packets to reassemble.
+ * The number of packets to reassemble
* @param param
- * applications use it to tell rte_gro_reassemble_burst() what rules
- * are demanded.
+ * Application-determined parameters for reassembling packets.
*
* @return
- * the number of packets after been GROed. If no packets are merged,
- * the returned value is nb_pkts.
+ * The number of packets after been GROed. If no packets are merged,
+ * the return value is equals to nb_pkts.
*/
uint16_t rte_gro_reassemble_burst(struct rte_mbuf **pkts,
uint16_t nb_pkts,
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
- * Reassembly function, which tries to merge inputted packets with
- * the packets in the reassembly tables of a given GRO context. This
- * function assumes all inputted packets are with correct checksums.
- * And it won't update checksums if two packets are merged. Besides,
- * if inputted packets are IP fragmented, this function assumes they
- * are complete packets (i.e. with L4 header).
+ * Reassembly function, which tries to merge input packets with the
+ * existed packets in the reassembly tables of a given GRO context.
+ * It doesn't check if input packets have correct checksums and doesn't
+ * re-calculate checksums for merged packets. Additionally, it assumes
+ * the packets are complete (i.e., MF==0 && frag_off==0), when IP
+ * fragmentation is possible (i.e., DF==0).
*
- * If the inputted packets don't have data or are with unsupported GRO
- * types etc., they won't be processed and are returned to applications.
- * Otherwise, the inputted packets are either merged or inserted into
- * the table. If applications want get packets in the table, they need
- * to call flush API.
+ * If the input packets have invalid parameters (e.g. no data payload,
+ * unsupported GRO types), they are returned to applications. Otherwise,
+ * they are either merged or inserted into the table. Applications need
+ * to flush packets from the tables by flush API, if they want to get the
+ * GROed packets.
*
* @param pkts
- * packet to reassemble. Besides, after this function finishes, it
- * keeps the unprocessed packets (e.g. without data or unsupported
- * GRO types).
+ * Packets to reassemble. It's also used to store the unprocessed packets.
* @param nb_pkts
- * the number of packets to reassemble.
+ * The number of packets to reassemble
* @param ctx
- * a pointer points to a GRO context object.
+ * GRO context object pointer
*
* @return
- * return the number of unprocessed packets (e.g. without data or
- * unsupported GRO types). If all packets are processed (merged or
- * inserted into the table), return 0.
+ * The number of unprocessed packets.
*/
uint16_t rte_gro_reassemble(struct rte_mbuf **pkts,
uint16_t nb_pkts,
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
- * This function flushes the timeout packets from reassembly tables of
- * desired GRO types. The max number of flushed timeout packets is the
- * element number of the array which is used to keep the flushed packets.
+ * This function flushes the timeout packets from the reassembly tables
+ * of desired GRO types. The max number of flushed packets is the
+ * element number of 'out'.
*
- * Besides, this function won't re-calculate checksums for merged
- * packets in the tables. That is, the returned packets may be with
- * wrong checksums.
+ * Additionally, the flushed packets may have incorrect checksums, since
+ * this function doesn't re-calculate checksums for merged packets.
*
* @param ctx
- * a pointer points to a GRO context object.
+ * GRO context object pointer.
* @param timeout_cycles
- * max TTL for packets in reassembly tables, measured in nanosecond.
+ * The max TTL for packets in reassembly tables, measured in nanosecond.
* @param gro_types
- * this function only flushes packets which belong to the GRO types
- * specified by gro_types.
+ * This function flushes packets whose GRO types are specified by
+ * gro_types.
* @param out
- * a pointer array that is used to keep flushed timeout packets.
+ * Pointer array used to keep flushed packets.
* @param max_nb_out
- * the element number of out. It's also the max number of timeout
+ * The element number of 'out'. It's also the max number of timeout
* packets that can be flushed finally.
*
* @return
- * the number of flushed packets. If no packets are flushed, return 0.
+ * The number of flushed packets.
*/
uint16_t rte_gro_timeout_flush(void *ctx,
uint64_t timeout_cycles,
* of a given GRO context.
*
* @param ctx
- * pointer points to a GRO context object.
+ * GRO context object pointer.
*
* @return
- * the number of packets in all reassembly tables.
+ * The number of packets in the tables.
*/
uint64_t rte_gro_get_pkt_count(void *ctx);
git.droids-corp.org / dpdk.git / commitdiff
